Lip Corner Botox: Where Do the Injections Go?

Lip corner Botox goes into the muscle just below and outside each corner of your mouth, close to the jawline. That muscle, the depressor anguli oris (DAO), pulls the corners down, so when it relaxes they drop less. If the injection drifts too far inward, it can also weaken the muscle that lowers your bottom lip, and your smile may look uneven.

Many people picture the needle going right into the corner of the lips. The target actually sits lower, and the exact spot and depth shape how natural your smile looks afterward. In this article, we'll cover how to tell muscle pull from lost volume, where the injection points sit, how upper and lower points compare, when to judge the result, which reactions are normal, and what to ask at your consultation.

Quick summary

• Mouth corner Botox goes into the DAO muscle, below and outside the corner of your mouth, near the jawline.
• Overlap: the inner edge of the DAO overlaps the bottom lip muscle, so a point placed off target can change how you smile.
• The muscle starts to weaken on day 2 to 4 and is at its weakest around day 10.
• Corners that droop because volume has thinned out won't lift with Botox alone.

Is a Downturned Mouth From Muscle Pull or Lost Volume?

A quick mirror test helps you tell the two apart. Pull the corners of your mouth down hard, as if you're making an exaggerated frown. If you see the muscle tighten and creases form from just below the corners toward your jaw, the muscle is dragging the corners down. That's the situation where relaxing it with Botox makes sense.

It's a different story if the area beside your mouth corners looks sunken and shadowed even when your face is relaxed. The same goes for deep lines running from the corners down toward the chin, often called marionette lines. That kind of droop comes from lost volume, so easing the muscle leaves the hollow where it is.

For a face like that, an option that fills the hollow, such as filler, is worth weighing alongside Botox. Many faces have a bit of both. At the consultation, the doctor compares your relaxed face with your pulled-down expression to see how much of each is going on and how the left and right sides differ.

Where Exactly Does Lip Corner Botox Go?

The target muscle starts just below the corner of your mouth and fans out toward the edge of the jawbone. It's thin and roughly triangular. Its inner edge overlaps the muscle that pulls your bottom lip down (the depressor labii inferioris). Its outer edge meets the muscles that lift the corners when you smile, along with a thin sheet of neck muscle called the platysma.

Because several muscles meet in such a small area, a needle that lands slightly off target can weaken a neighbor too. That's why placement matters more here than in many other Botox areas.

Research points toward the lower part of the muscle. In an anatomy study of 42 half-faces, the fan-shaped area close to the edge of the jawbone was described as the safest and most effective place to inject. Ultrasound scans of 41 people found the muscle in the middle and lower part of the marionette line area, about 4 to 5 mm under the skin. In roughly one in three of those people, there was barely any of this muscle in the upper part of the line, so a point placed high may have little to act on.

At the visit, the doctor looks at the balance of your whole face and the height of each corner first. Then you'll be asked to make a few expressions while the doctor feels where the muscle pulls, and the injection points are marked from there.

Does a Lower Injection Point Lift the Corners More?

Lower points tend to work better, though they come with a trade-off. A study that compared injections in the upper and lower parts of the same muscle found that the lower point reduced the muscle's pull more, with no serious side effects reported.

The catch is that the overlap with the bottom lip muscle grows as you move down toward the jaw. Measured on the same 41 ultrasound scans, the two muscles overlapped by different lengths in each zone:

• Upper zone: about 4.74 mm of overlap
• Middle zone: about 9.68 mm
• Lower zone: about 14.54 mm

So the spot that works best is also the spot where the neighboring muscle is closest. When the lower point is used, the needle stays toward the outer side of the DAO and at a shallow depth to keep the bottom lip muscle out of it. Keep in mind that how much lift you see still differs from person to person.

When Do DAO Botox Results Show, and When Should You Judge Them?

The muscle starts to weaken 2 to 4 days after the injection and reaches its weakest point around day 10. After about 3 months, the connection between nerve and muscle rebuilds, and the downward pull gradually returns.*

*Based on DermNet guidance on botulinum toxin.

That's why the result is best judged 10 days to 2 weeks after treatment. If the corners look barely lifted at the end of the first week, the muscle simply hasn't finished relaxing yet. Topping up the same spot before then can stack the doses, which raises the chance of your bottom lip drooping too. Waiting until the full effect has had time to show gives a clearer picture.

When you check, use the same two expressions as before: your relaxed face and the pulled-down frown. Photos taken in the same light and from the same angle make it much easier to see what changed.

Mouth Corner Botox Side Effects: What Passes and When to Call Right Away

Most reactions after this treatment come from the needle itself and pass on their own. Here's what tends to settle without help:

• A brief sting where the needle went in
• A small bruise, mild swelling, or redness for a few days

Weakness spreading to a nearby muscle is uncommon, happening in fewer than 10% of treatments. When it affects the lips, it can last up to 12 weeks, because the effect has to wear off on its own.

Don't wait it out if you notice any of the following. These signs can appear a few hours after treatment or even weeks later, so contact the clinic right away:*

• A crooked smile or drooling
• Trouble speaking or swallowing
• Breathing problems
• Vision problems, or muscle weakness elsewhere in your body
• An allergic reaction

*Based on Mayo Clinic guidance on Botox injections.

If speaking, swallowing, or breathing becomes difficult, get medical care right away instead of waiting for a reply. A message to the clinic doesn't replace an in-person exam.

It's better to postpone treatment in these cases:

• You're pregnant or breastfeeding
• You have a condition that weakens muscles, such as myasthenia gravis
• There's an infection where the injection would go
• You've had an allergic reaction to botulinum toxin before

Planning Lip Corner Botox Within Your Travel Itinerary

Unless you had sedation that day, there's no reason to postpone your flight because of lip corner Botox.

It also helps to know what a single visit can do. Most treatments change your look gradually rather than dramatically in one session, and this one works over several days as the muscle relaxes. How much the corners lift and how long the effect holds can't be promised in advance.

Once you're home, you can contact the clinic with photos if you have questions about how your result is settling. If a strong warning sign appears, such as trouble swallowing or breathing, see a local medical facility first rather than waiting for a reply.

The Bottom Line: How Far Down Does Your DAO Reach?

The variable worth taking into your consultation is how far down toward the jawline your DAO muscle reaches, since that decides where the lower injection points can sit and how deep they go. Ask the doctor: "How far down does my DAO reach, and how deep would you inject it?" If the area beside your mouth corners looks hollow, also ask whether Botox alone fits your face or whether filling that hollow should be part of the plan. Beautystone is a clinic in Seoul's Hapjeong area. When you send us a message using the button on this page, include a photo of your relaxed face, a photo with your mouth corners pulled down, and the dates you'd like to come in.

References

• Where the DAO muscle sits and the safest area to inject, an anatomy study (Plastic and Reconstructive Surgery, 2014)
• Ultrasound of 41 people showing DAO depth and its overlap with the bottom lip muscle (Aesthetic Surgery Journal, 2024)
• Comparing upper, lower, and added neck muscle injection points for a downturned mouth (Plastic and Reconstructive Surgery, 2026)
• When botulinum toxin takes effect, who should avoid it, and how often nearby muscles weaken (DermNet)
• Reactions after Botox and symptoms that need prompt care (Mayo Clinic)

Frequently Asked Questions

Q. Does lip corner Botox hurt?

A. Lip corner Botox usually feels like a brief sting from a fine needle at a few points. A small bruise or some tenderness where the needle went in is a common reaction. If you're worried about discomfort, the anesthesia method is decided together at the consultation.

Q. How long does DAO Botox last?

A. DAO Botox typically lasts about 3 to 4 months, after which the pull of the muscle gradually returns. How long it holds varies from person to person, so the timing of a repeat session is based on when you notice the effect fading.

Q. Can I lie down right after mouth corner Botox?

A. It's best not to lie down for 2 to 4 hours after mouth corner Botox. Don't rub or massage the injected area for 24 hours either. Both steps help keep the medicine from spreading to muscles it wasn't meant for.

Q. How often can I repeat lip corner Botox?

A. Lip corner Botox is usually repeated at least 3 months apart. Getting it more often than every 8 to 12 weeks can lead your body to make antibodies against the medicine, which may make later treatments work less well.

Q. I take a blood thinner like aspirin. Can I still get mouth corner Botox?

A. A blood thinner can make a bigger bruise at the mouth corner Botox injection site. Don't stop the medicine on your own; tell the doctor the names of everything you take before treatment. Sometimes the treatment date is set after checking with the doctor who prescribed it.

Q. What changes if the neck muscle is treated along with the DAO?

A. Adding the platysma, a thin neck muscle, to DAO injections improved mouth corner position at 1 month and at 6 months in a comparison study, and satisfaction was higher than with the DAO alone. It's an option worth weighing when the neck muscle also pulls the corners down.

Q. Is mouth corner Botox the same as jaw Botox?

A. Mouth corner Botox and jaw Botox target different muscles: jaw Botox goes into the chewing muscle at the side of the jaw (the masseter), while mouth corner Botox goes into the DAO below the corners of the mouth. Jaw Botox works on the outline of the lower face, and mouth corner Botox works on the downward pull at the corners. Whether to do both is decided at the visit.