What are my options to reduce round chubby cheeks, especially when smiling? (photos)

I believe you are good candidate for buccal fat removal. It will provide better definition to your cheeks by slimming your lower face

Thank you for your question and photos. Buccal fat pad removal is an ideal procedure for reducing excess fullness in the midface beneath the cheekbones. This surgical approach can slim a rounded facial appearance while creating a more contoured jawline.
Since buccal fat tissue is not regrown, the results of this fat pad removal are permanent. I recommend scheduling an in-person consultation with an experienced, board-certified facial plastic surgeon who can assess your concerns and suggest the best approach.

Hi there! Buccal fat removal involves removal of the fat from the cheek area via an intraoral incision. It's often described to be the volume of a walnut. It helps to create shadowing from the high cheekbones to the jawline. The result in most cases is subtle though noticeable. The recovery is minimal and it may be a good option for you. Other options would be Morpheus8 microneedling along the cheeks and jawline. This will help to tone the skin, though not to the same degree as a surgical result. Hope this helps!