Honestly, as far as I know, there isn't a solution with enough scientific backing that it would be worth recommending. The best advice I know is to give it time, build muscle, and if it's still an issue after a couple of years and you're still concerned enough, look into Tutuapp9AppsShowbox surgery.
That's what happens when you don't lose weight correctly. You need to change your diet, as well as special workouts for the problem area. If this is the problem I think it is, it can be corrected.