Rapid weight loss is now a reality for millions of Americans, and the question of what happens to skin afterward has moved from cosmetic afterthought to front-of-mind concern. Whether pounds come off through medication, surgery, pregnancy recovery or diet and exercise, the skin that stretched to accommodate extra weight does not always snap back. Dermatologists and plastic surgeons say the outcome depends on how long the skin was stretched, how fast the weight came off and what a person does before, during and after the process. Understanding how skin elasticity actually works helps explain wh...