To reduce facial fullness, it's important to understand the primary cause of this physical trait. When someone smiles and their face appears quite round or full without definition, the fullness is often due to large buccal fat pads. While prominent masseter muscles can also contribute, they are not the primary cause. Therefore, if someone wishes to reduce facial fullness, the procedural option is buccal fat pad removal. By removing the excess buccal fat pads, the face will appear more contoured, with better definition, and will no longer have a chubby appearance, especially when smiling. Botox injections to the masseter muscle can decrease the fullness of the masseter, located in the lower posterior section of the face, which may make the face look thinner and more V-shaped in individuals without enlarged buccal fat pads. However, if someone undergoes masseter Botox injections and has chubby cheeks, this can make the face appear even chubbier. Reducing fullness in the lower posterior face can accentuate the appearance of enlarged buccal fat pads, leading to an overall chubbier look. I hope this helps! Sincerely, John Mesa, MD Buccal Fat Removal Specialist Plastic Surgeon New York - New Jersey - Miami.