Dear rcdivina, Thank you for your clinical post and question. If you actually meant buccinator muscle, this is a deep muscle in the cheek and behind which the buccal fat pad resides. The buccinator helps during mastication and phonation and injecting it with Botox will not change your facial appearance at all. However, if you meant the masseter muscle injecting this with Botox can definitely decrease the transverse width of your lower third of your face. This is more common in certain races such as a Japanese and Korean faces who have large hypertrophy masseters and injecting them can provide a much more oval look. Generally, 60 or more units is required in each masseter and this will soften the mandibular border and angle in those individuals with wide lower faces. I hope this information is of some assistance and best of luck. To find out more, please visit the link below. R. Stephen Mulholland, M.D. Certified Plastic Surgeon Yorkville, Toronto