I Had Botox in my Masseters 2 Days Ago, when I Can Expect to Notice Any Effect? (photo)

The sequence is the following:1) botox injection 2) within 2 weeks, you should feel that your muscles can't clench down as hard3) Over the course of the next many weeks, the masters will slowly shrink and your face will slowly slim. This is due to the muscle atrophying as a result of not working as hard (analogy: if you have your arm in a cast for a few weeks, it will be smaller than the other arm when the cast comes off). People normally notice reduction in grinding/clenching and less discomfort/tension within the first couple weeks.  The changes in facial shape are more gradual.

It can take up to 2 weeks for the full effect of anti-wrinkle injections (Botox) to the masseter muscles.  Usually these patients are seen every 6 months for re-treatment, but after regular treatments it can last longer due to the retraining of the muscles treated.

Usually two weeks after Botox injections patients begin to see and feel a difference from the injection. Because the muscle is so strong, it requires a bit longer than the forehead muscles to fully react. You will notice a lessening in the strength and degree of the muscle over the next few weeks. Visual reduction may take a few months and we usually retreat at 3-4 months and then wait another 6 months for full visual shrinking of the musculature.
My best, 
Dr. Anil Rajani

Thank you for your question. Botox in the masseter region usually takes longer than in the standard areas to take effect. I tend to use anywhere from 15 units (conservative treatment) to 50 units (for someone with really strong masseters) on each side to get the desired result. It may start within the first week but I tell my patients to wait three weeks before doing a more thorough evaluation. The treatment typically lasts longer than the forehead/crows feet/frown regions. It is also a gradual onset of the return of masseter function. I have tried the masseter injections myself and space the treatments around 4 months apart, but use smaller doses to maintain the effect. I normally know the effects are wearing down when I start to clench my teeth more heavily at night when asleep. Once you stop using Botox, the masseter muscles will return to their original baseline when the effects of Botox wears off completely.

Botox usually takes 2 or 3 days to start to work, and will continue to improve over the first 7 to 10 days. Once the effect starts to wear off, you will need a repeat treatment to maintain results. Some find that the effects last longer after having multiple treatments, even up to a year.