Everyone is correct - excess skin is a by product of rapid weight loss.
I would check with your insurance company. Careful how you phrase the question though. No insurance will cover a tummy tuck because you don't like the way you look. However, several insurance plans will cover it if you are experiencing infections, dermatitis, or other skin conditions as a result of the excess skin.
Just like your WLS make sure you know your insurance plan rules and exclusions. Ask what the medical criteria is and go from there.