Breast depression after breast augmentation may be due to surgical failure, implant displacement or cell necrosis. 1. Surgical failure: if patients use hyaluronic acid injection for breast augmentation, and breast depression occurs, it is usually due to uneven injection of hyaluronic acid, and this symptom may be recovered with time, but the long-term existence of this situation proves that the surgery has failed. 2. Displacement of implant: The use of silicone gel implant for breast augmentation may lead to displacement of the implant when it touches the surgical site after augmentation, thus resulting in the occurrence of breast concavity. 3. Cellular necrosis: Breast hollowing after breast augmentation with autologous fat transplantation is usually caused by cellular necrosis due to the rejection of implanted fat. After breast augmentation, breast depression should be examined and treated in hospital in time, and the cause should be identified and treated according to the doctor’s instruction.