Masseter jaw reduction Botox 1 week ago and absolutely no changes. My masseters are big and strong. (Photo)

Yes, it can take up to 2 weeks for final results with Botox for the masseter. I would wait the full two weeks before assessing whether you need additional Botox. Hope this helps.

The masseter muscle is a powerful muscle, and in my experience usually takes longer than 2 weeks to see not only inactivation but atrophy (shrinking of the muscle). As some of the posters noted, it can take several rounds spaced every 3-4 months to get clinically meaningful results. Good luck!

Thanks for your question. Your injector should have explained to you that atrophy of the muscle will take weeks to months after the injection. These muscles are too big to be fully paralyzed and you may need a second or third treatment every 3 months or so before you get final results! Be patient. 

In certain individuals, large masseter
muscles can contribute to the appearance of a square jaw. Botox injected into
the Masseter muscle can temporarily weaken parts of the Masseter to cause it to
shrink in size and make the jawline
appear slimmer. As with any muscle, it
takes a while for the muscle to start
shrinking after it has been paralyzed.
Botox usually begins to work ~ 3 days after injection, and it can take up to 2 weeks for the full effect of the Botox to
take place.  The final effect of the
Botox will depend on how large your masseter muscles are and how many units of
Botox were used. At 1 week after injection,
it is normal not to see a drastic change yet.
 In instances like this, I would recommend waiting another week,
and if you still do not notice an improvement in
your jawline then you should visit
your injector to see if you would benefit from more Botox.

Thank you for the question and photo. 
It is too early to say. You can't make any assessment of the result from BOTOX for 2 weeks. It is not uncommon to need more than one treatment when you have a very strong and bulky masseter to start with. 
In future I would make sure you know more about what is being injected (What product? How much? Where?). Any experienced and reputable injector will not hesitate to discuss this with you.
Good luck!
Dr Chris Macdonald
CRM Aesthetics

It can take up to two weeks to see the full effects of Botox. If at two weeks you still feel that you are not seeing a change I would recommend scheduling a follow up appointment with your injector. At that time they can determine whether or not you need additional units. 

In contrast to BOTOX of the upper face, which starts to show results in about 7-10 days after injection and lasts approximately 3-4 months, Botox injected into the masseter takes almost 6 weeks before results are noticeable but it lasts a lot longer usually 6 months. 
Be patient, this is one of my favourite treatments for Botox it typically gives dramatic results. 

It will Take up to 2 weeks for the results of the masseter treatment to take effect. Be patient wait the full 14 days before assesing the need for additional Botox. I sure hope this helps. 

I wouldn’t get too concerned about the results yet. Botox can sometimes take up to two weeks. However, after two weeks if you are still unsatisfied I would follow up with your provider. It is possible more units of Botox could be needed. Good luck!

One week is not long enough to determine the effectiveness of Botox injection of the masseter. since the masseter is so large it may take even longer than the usual 10 days or so to even begin to see results so give it more time