One of my masseter is larger than the other. After Botox, how long does it take for the muscle to get smaller?

Thank you for your question, and I am sorry that you have not yet gained the results you are looking for with Botox.  Botox works by preventing nerve-muscle communication, resulting in muscle atrophy with time.  This is not dissimilar to stopping an exercise regimen, your muscles will gradually reduce in size.  Though you can make the masseters slimmer, it will take several treatment cycles, and months, for the effects to take place.  Hang in there!  Be sure to see a board certified plastic surgeon as this is an advanced Botox technique

This is a process that takes time. It is a little different from person to person and it is difficult to estimate how long it will take, but you will get there.,Hope this helps,Dr. Gus Diaz