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.

Usually Botox injected in the masseter muscles can minimize teeth clenching, not grinding. After the clenching diminishes, the muscle starts to become less hypertrophied, or bulky. Just like a weight lifter who stops working out; the muscles are still going to be bulky for a while. There is a gradual diminishing of girth.

You won't see a change until about 7-10 days.  Depending on the dosage used by your physician, and where in the body of the masseter muscle he injected, the degree of "tapering" and change will vary.  Typically 4-5 injections are performed on each side along the inferior border of the muscle, but taking the injections more superiorly does help to enhance the final result.  The Botox will have worn off in 3-4 months, so 9 months is too long to wait for a repeat injection.  Even with the largest muscles you will see a visible reduction in size with proper technique after one injection, though you may not achieve the maximal reduction possible with Botox until you have had 2-3 sessions.    

Hi and great question! Botox does take a few days (7-14 average) to take affect and it is not concerning yet that you haven't noticed change. Always be confident that you can follow up with your provider after 2 weeks if you aren't noticing relief or affect. Dosage is commonly communicated in our practice for patient education purposes, but it's a benefit to you and your provider to have excellent communication so the appropriate dosage is administered. I also agree that 9 months seems a lengthy distance between appointments as the Botox will commonly wear off 3-4 months following treatment. There are patients who do see longer effects with treatment, but once you get the first concern out of the way- being certain that the Botox is dosed appropriately and you have results you're pleased with- it will also benefit you to assess yourself 3-4 months from now. With repeated treatments of Botox, the muscles do not have the opportunity to gain full strength and go back to "pre-treatment" state. This is true of dynamic muscle activity anywhere Botox is effective. Again, it's too early to worry about the treatment you just received, but don't ever hesitate a follow up to the office 14 days following treatment if you're unsatisfied with the results. Sometimes a few more units are needed and it's best to not overtreat initially. It's also not a good idea to assess too early, or before the 2 week period. I hope this brings confidence in the treatment and helps you to know experiencing little change thus far is very normal.

Assuming this is your first injection of Botox, you should start feeling the effects within 2 weeks. Without knowing how many units were injected to your masseters, it's difficult to say how much of a reduction you'll see over the course of the next few months. I would check in with your provider when you start to feel like you can clench and grind again, (the Botox is wearing off), then determine how much contouring was achieved and formulate a long-term maintenance plan.

Hi rt066,
Thank you for your question and photos!
Botox to the masseter muscles is a great treatment to improve jaw clenching/teeth grinding, along with improving facial shape and slimming the face. 
Botox begins to kick in around day 3-4 and reaches full effect by 2 weeks. At this 2 week mark you should notice a decrease in your teeth grinding and clenching. However, it can take up to 30 days to notice the slimming effects from Botox. This is because the muscle needs time to decrease in size from not being used as frequently. For the masseters we typically  recommend treatment every 6-9 months.
I've created a video that reviews Botox/Dysport treatment to the masseter muscles, I hope you find this helpful in your research!