Hey TCB,
Actually it's a medical procedure, not cosmetic. You should consult your surgeon and primary doc. If you document rashes with treatment for a period of time, and having weight loss procedure (such as lap band) to help with weight loss, most insurances do cover it.
You just can't say "tummy tuck", it's either a panniculectomy or abdominoplasty. You should call your insurance as well and ask them what the process would be for skin removal after weight loss surgery.
Good luck and let me know how it goes.
Jen