Masseter muscle enlargement (hypertrophy) can be accompanied by pain and can be caused
Botulinum Neurotoxin Treatment (BoNT)
Although the largest reported experiences with use of BoNT come from the cosmetic use for facial recontouring, it has been used successfully to treat masseter hypertrophy to address pain associated with unilateral enlargement.
The use of Botulinum Toxin can:
Through a sequence of three injections to the left masseter in 3 points of injection 5 units (15 in total) in a triangular spacing. Be careful not to come off the Masseter into other muscles causing asymmetrical facial expressions.
One study found that Initial treatment resulted in 3 months of benefit with the second injection more durable but still warranting a third injection one year after the second.
Weak chewing function