How can I get my insurance to approve reconstructive surgery after Gastric Byp Surgery?

I had Gastric Byp Surgery 18 months ago and went from 282 lbs to 125lbs! I have hanging skin issues and it is very humiliating. I walk around in the summer in longer sleeve tops and jeans! I won't wear a bathing suit! I am very healthy but very miserable! I feel they have left me half done!! I have no rashes or sores or anything and my insurance company won't help me! Can anyone please give me some advice on where to turn! It would be greatly appreciated! I am very depressed and discouraged!