Am I a good candidate for masseter Botox? (photos)

Botox for your masseter muscles may be helpful for both reasons you listed. For the jaw pain and teeth grinding, you may be able to get your insurance to pay for it under bruxism or oral mandibular dystonia diagnosis. About 25 units into the masseter muscles should work. You can put more on the worse side if needed to make your jaw line more symmetrical. For the jaw pain and teeth grinding you may want to also have the temporals muscles injected. See an experience injector.

1. Using toxins to reduce the pressure load on TMJ can relieve symptoms but not necessarily wipe out all symptoms. Need to discuss with an experienced injector, be physically assessed in person and try it! Avoid those that use the same dosage for all patients.
2. Sometimes the asymmetry is due to mandibular bone differences and injecting masseters alone may not achieve a patient's expectations.
3. Agree the chin was not done beautifully and should be modified. If HA fillers are used, it can be enzymatically reduced and reshaped.

From your photos and description it seems you are a good candidate for masseter Botox. The treatment will be in full effect after two weeks and the results will fade gradually over three to four months. Meet with an experienced injector to discuss your concerns and receive treatment.

Botox can be a very helpful treatment for those with clenching and grinding, migraines related to the former activity, and for reshaping the face and creating better symmetry. I'd have to palpate/feel the left masseter in your case to assess how large and firm the masseter muscle is before deciding on a dose, but one might start with 24 units spread out over 3 injection points; if the improvement is good, but not good enough, then can increase your injection the next time around to 30 units. Best to see your local dermatologist/Botox injection expert as the anatomy is very important to avoid unwanted side effects (ie. unintentionally affecting the risorious muscle which would make your smile look odd for 3 or so months).