Pain when chewing 2 months after botox in the masseter - What is going on?

As a dentist you probably know that at times it is difficult to pinpoint the origin of the pain as it may be felt by the person a distance from the affected nerve. In terms of the pain that is experienced with biting, I wonder if there is an imbalance between the right and left sides since so double the units of Botox were injected on the right than the left. I assume that the right was more enlarged than the left but it is possible that after the Botox, the bite is malaligned , or you may be compensating with a different muscle, such as one of the pterygoids,  that is not normally clencing as strongly as it is now trying to function in place of the relaxed masseter on that side.I would suggest seeing a dentist or oral surgeon who specializes in TMJ to determine with appropriate scans if necessary if there is a significant imbalance from right to left and if there is, question if more units on the left could create more symmetry and less strain.The information provided in Dr. Shelton's answer is for educational purposes only and is not intended to constitute medical advice.  The information provided should not be relied upon as a substitute for consultations with a qualified health professional who may be familiar with your individual medical needs. 

It is unlikely that this is being caused by Botox as it wears off after 3-4 months, that would be a very delayed onset. Please, see your primary care physician if this persist. Best, Dr. Emer

Dear twinklecateyes, If the symptoms persist I would recommend seeing a board certified plastic surgeon or oral surgeon for evaluation. There are several muscles that control chewing. Inactivation of the masseter may be overworking the others, but it is impossible to tell without an in person evaluation. Also, there are other causes of pain during chewing that are joint related. Surgeons with facial expertise (craniofacial, oral surgery, ENT) have an in depth understanding of this anatomy and will hopefully be able to give you an answer.Good luck,Nirmal R. Nathan, M.D.
Certified, American Board of Plastic Surgery
Member, American Society of Plastic Surgeons

Hi twinklecateyes, We usually inject 15 -25 units for starters for masseter reduction. It is possible that the amount injected has weakened the muscle more than intended. This is why there is more effort towards chewing on the right. You need to have your Injector test the muscle strength of your masseters. For now until about the third month or so  when the effects start wearing off, you need to favor your left side for masticating. All the best, Justin Harper, M.D.

Dear Twinkle,Sounds like you should have a formal evaluation and exam of your mouth by your pcp, to evaluate for other causes of pain.Best. Dr Brecht Seattle, Wa