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

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