Will i have loose skin if i lose 80 pounds in a couple months?

Possibly: Every person has a particular genetic skin quality. I have seen people loose a lot of weight and not have hardly any skin laxity; other people have dramatic skin laxity. I have seen the most laxity come from surgical weight loss patients following gastric bypass. Generally, weight loss with diet and exercise seems to do better for skin laxity. Loose skin or not you are better off losing weight.

Loose skin : Skin contraction or shrinking after weight loss depends on the quality of your skin. If elastic fibers in the dermis have been damaged by weight gain then the skin will likely be loose after such a large weight loss over such a short time. Stretch marks are a sign of skin damage and poor skin quality and indicate a very high probability of loose skin after weight loss.

Yes but where?: Following massive weight loss individuals experience different patterns of skin contraction that vary depending on the nature of the localized deposits, the individual's genetic tendencies and skin elasticity and age and many other factors. In women tummy tucks (witch hazel) & breast lifts/augmentation are the two most common surgeries following massive weight loss: (face, arms, neck, thigh, buttock lifts, etc).