Double crease under one side of my buttocks. What is the best solution to help get rid of this crease? (photos)

I have always had a double crease under one side of my buttocks. I have exercised for over 3+ years doing targeted gluteal exercises 3 days a week but nothing is resolving the problem. It has improved slightly but the unevenness is still there and I cant see it going away! I worked so hard to try and make improvements I feel doing something cosmetic is my only option now What is the best solution to help get rid of this crease? I don't have a lot of fat and I have a fairly athletic frame