Gynecomastia indentation solutions?

Unfortunately, this is not uncommon. The solution really requires an examination to see if the surrounding area needs liposuction to make it a more level area or whether you need a filler for the depression, or even a combination of the two.
For filling, you need a more permanent filler. Fat grafting is more permanent but does require at least minor surgery to procure the fat and then the injection, but it should be successful.
A new product called Renuva is an excellent choice in my opinion because it will last at least 5 years in their studies, and it is estimated that it may last 10 years. Renuva injections stimulate your body to product your natural fat in that area. We have not had any disappointed patients who have had these injections. I have used it in the face, buttocks, and other depressions with success.

It's hard to say without seeing a photo, but fat grafting can be done in the office under just local anesthesia. If you don't have enough body fat or don't want a procedure, Renuva is an option. It's an injectable fat scaffold from donor cadavers that stimulates you body's only fat to grow into it. It'll give a more subtle result and would probably be more costly than in-office small volume fat grafting, but is an option.

It is very hard to give opinion without any photos to review. However, considering the area and nature of deformity, fat grafting would, most likely, be best long term option. In person or teleconference consultation with a board certified plastic surgeon or recommended. Good luck.