I got Botox injected into my masseter muscles about 5 days ago and I believe it has made my masseter muscles even bigger.

The doctor did one injection on each side and I am unsure of the amount. However, now, when I clench my teeth, the masseter muscles protrude out even more than they did before the botox. I'm very confused, I don't have any pain and am not sure if this is swelling because I can only see the enlargement when I clench. Thanks in advance for any help!

Doctor Answers 12

Botox and Dysport for jaw slimming

Thank you for your question. Botox or Dysport can be a very effective way to contour the jaw line by reducing the masseter shadow through the outer jaw skin. In addition, it can reduce symptoms of jaw clenching or grinding of teeth at night time. This is an advanced technique that requires a strong understanding of the underlying anatomy. Some side effects can results in some very unintented effects. This can include affecting the smile due to diffusion of the Botox into neighboring smile muscles. Over treatment can also overweaken your jaw muscles making it harder to chew food and causes your jaw muscles to relax too much when you sleep.
The injection technique does vary by physical exam and the goals of the treatment. Facial contouring goals may change the injection sites themselves to affect different portions of the masseter as well as the dose. The strength of the masseters can be felt by palpation and also helps me to determine dosing. In general, I start with 15- 25 units of Botox (OR 50-75 units of Dysport) per side for most patients. If they have very strong masseters, then I may increase the dose, but more commonly ask them to return in three weeks for a touch up. If you notice one area bulge after the procedure, then a small dose may be required to quiet that portion of muscle.

Once you get the desired result, I let patients know that future treatments may require less to maintain the look or the jaw clenching symptoms, especially if they get treated as soon as they notice the symptoms return. This can be as soon as three to four months, but in some cases, patients report that it lasts six months or more. I find it depends on the dose we use and how many times we have done the procedure as the duration may lengthen for patients that repeat it regularly.

Houston Plastic Surgeon
4.8 out of 5 stars 37 reviews

Typically there are 3 injections administered to treat the masseter muscle.

Typically there are 3 injections administered to treat the masseter muscle. Speak with your injecting physician to discuss your results or obtain a second opinion. 


Martin Jugenburg, MD
Toronto Plastic Surgeon
4.9 out of 5 stars 457 reviews

Botox to jawline muscle causing a bulge

This happens on occasion and is easily remediable by returning to your injecting doctor and have him/her place 5U into the bulge. It may resolve on its own but generally I have my own patients return for this. We have been performing this since 1999 and have the largest reported series at the time we first introduced the technique to North America.

Charles S. Lee, MD
Beverly Hills Plastic Surgeon
4.5 out of 5 stars 78 reviews

Botox for the Masseter muscle - what to expect

Treating this large muscle can be very rewarding aesthetically as well as clinically.  

Most practitioners will use a 4-5 injection sites per muscle in a dice-like pattern directly into the bulging portion of the muscle.  Having only one injection site can limit the full effects of your treatment as well as lead to more muscle tenderness and swelling by placing all the solution/product into one injection site. 

We recommend following up with your injector for an assessment.  Although the benefits of treating this area is slow and progressive, your practitioner will be able to determine if there are any causes for concern and how to monitor your outcomes.  

The link below will offer more feedback as well as before and after photos of our jaw reduction patients in Los Angeles and Orange County.

Harold J. Kaplan, MD
Los Angeles Facial Plastic Surgeon
4.3 out of 5 stars 6 reviews

Botox to Masseter

Thanks, this is a great question.  We see these types of cases quite often and have been using Botox, Xeomin or Dysport to reduce Masseter Hypertrophy for over 25 years.  The dose of Botox, or equivalent amount of Xeomin or Dysport, depends on the size of the Masseter enlargement and whether this is the first neurotoxin treatment or one of serial injections. First treatments typically consist of 50 - 75 units of Botox using multiple injections over the enlarged muscle area.  We recommend repeating this dose at 4-6 month intervals until the desired result is achieved.  For isolated areas of muscle enlargement, the dose can be reduced as well as the number of injections sites.  We typically then massage the neurotoxin into the Masseter following the injections.

As with any needle based therapy, bruising and swelling can occur though this is typically very limited. Aspirin, Fish Oil, Vit, C/E and other blood thinners can increase this effect.  Botox and other neurotoxins weaken muscles and can't increase the size of that muscle.  It's importnat to appreciate the fact that actively contracting the treated muscle, in this case the Masseter by clenching, will encourage new neuro-muscular junctions to form sooner thus decreasing the longevity or duration of the neurotoxin effect.  This should be avoided following any neurotoxin treatment.  Hope this helps.

Francis R. Palmer, III, MD
Beverly Hills Facial Plastic Surgeon
4.6 out of 5 stars 24 reviews

Botox treatment for masseter muscles

It can take up to two weeks to see the full result from your Botox treatment.  One injection site may not be enough if you have well-developed masseter muscles.  Comparison with previous photos would help.  The swelling may be bruising but please return to your physician for assessment.

Martie Gidon, MD, FRCPC
Toronto Dermatologist
5.0 out of 5 stars 22 reviews

Botox to treat the masseter

Thank you for your question. Botox can take 5 to 10 days for the results to set in, you could be experiencing swelling in that area. If it is abnormally larger I would suggest letting your doctor know so you can get in for a follow up appointment.

Best Wishes,

Pablo Prichard

Pablo Prichard, MD
Phoenix Plastic Surgeon
5.0 out of 5 stars 47 reviews

Botox into Masseter

Botox can take up to 2 weeks to see its effects. The masseter is a large muscle, so depending on how many units you got in the first session, you may require more to achieve your desired effect. The enlargement you are describing may be related to swelling or some bleeding with hematoma formation in the deep tissues. You should schedule a follow up appointment with your injector to have your concerns addressed. Good luck to you.

Michael A. Zadeh, MD, FACS
Sherman Oaks General Surgeon
5.0 out of 5 stars 10 reviews


It takes up to two weeks for the muscles to atrophy, I would give sometime to calm down.  If you have swelling or pain, tylenol and cold compresses help.  Best, Dr. Emer

Jason Emer, MD
Los Angeles Dermatologic Surgeon
4.8 out of 5 stars 190 reviews


It can take up to two weeks to see the desired result. However. I think you need to check with your doctor. This could all be swelling

David A. Bray, Sr., MD
Los Angeles Facial Plastic Surgeon
4.4 out of 5 stars 7 reviews

These answers are for educational purposes and should not be relied upon as a substitute for medical advice you may receive from your physician. If you have a medical emergency, please call 911. These answers do not constitute or initiate a patient/doctor relationship.