Yo all. Im 17 years old right now, and 3 years ago I successfully lost 40kg. I have always noticed the excessive skin, but doctors and advisors said that it would just tighten up naturally like elastic (it hasnt.) i've been training kinda on and off for 3 years now and, though I can definately feel my abs, they still arent visible behind all the excess skin. Basically I want everyone's opinion as to whether I need the surgery, or are there some excercises that I can do to tighten the skin? Any help much appreciated, thanks.