Mouth and lips or perioral region fat injection rejuvenation results depend on understanding perioral anatomy and perceived signs of aging. The principal areas of the lower face that benefit from fat augmentation are the pre-jowl sulcus, labio-mandibular recess, labio-mental sulcus, lateral jawline, and anterior central mentum. The perioral region is amended for improvement with millifat, microfat, and nanofat. Besides, pyriform augmentation with millifat will affect the lifting of the upper lip. Buccal atrophy is consistently seen in the fourth decade of life and beyond, as is buccal hollowing caused by previous overzealous excision of buccal fat or human immunodeficiency virus-associated facial wasting. Asymmetrical fat placement is often required on the right and left sides because of the frequent buccal asymmetry seen preoperatively in many patients. Fat transfer can correct age-associated loss of chin volume, loss of chin projection, and loss of vertical chin height, and in some cases, can rival the kind of improvements obtained when small chin implants are placed. Fat transfer of the chin can also correct an atrophic and feeble appearance. When indicated, the button shrinks with age by broadening and strengthening it and filling the labio-mental and submental creases. Fat transfer along the mandible can also correct an atrophic and feeble appearance as the mandibular border shrinks with age by broadening and strengthening it. Treatment of the jawline typically must be undertaken in conjunction with the pre-jowl groove, and the two areas overlap in most cases. However, patients seeking a quick recovery, a specific lip size or shape, or subtle changes are not optimal candidates for the procedure. Patients should also be advised that it is impossible to create the highly stylized cover-girl lip appearance seen in fashion magazines when using fat.