If the concave scar surface is not very rough, it can be filled with autologous fat transplantation. If you can send a photo, I can give you a more detailed plan.

(Dr. Wang Benfeng from Shaanxi Provincial People's Hospital solemnly reminds me that because I can't see the patient face to face, I can't fully understand the condition. The above suggestions are for reference only. Please go to the hospital for specific diagnosis and treatment under the guidance of a doctor! )