Facial fat grafting is a procedure in which the patient’s own fat, harvested via liposuction from areas such as the abdomen or thighs, is purified and injected into sunken areas such as the cheeks, forehead, and under the eyes. According to the Cleveland Clinic, this is typically an outpatient procedure, and while the area may appear excessively swollen immediately after the injection, the swelling subsides over 1 to 2 weeks, revealing the final results. An important characteristic is that not all of the injected fat cells take root. According to the data, it takes about 6 months for a new blood supply to establish itself and for the final results to become apparent; a significant portion of the transplanted fat may be absorbed over the course of 3 to 6 months, so additional procedures may be necessary to achieve the desired volume. Absorption and survival rates vary significantly from person to person. During your consultation, it is advisable to discuss the harvest site, the expected degree of absorption, the recovery period for swelling and bruising, and the differences compared to other methods, such as fillers. This information is for informational purposes only and does not constitute a diagnosis. Please consult a specialist regarding the actual procedure.
[Source] https://my.clevelandclinic.org/health/treatments/24027-fat-transfer