Shilah,
I went to a support group meeting where someone asked that question. The answer was that not everyone has the hanging skin and they indicated that it was most likely genetic. Secondly they recommended that you wait about two years after your weight loss to have plastic surgery because some of the natural elasticity might return and make the surgery easier. I have also heard some people have been told to stop losing weight because they estimated the amount of weight you would lose if they did plastic surgery. I think age and physical condition has a lot to do with it because your skin ages just like you do. It is amazing what you can learn in a support group, things I never thought about before.