M.L.
I'm pretty sure that surgery or wearing a spanx are the only real cures for loose, hanging skin, if it's a lot of skin. It isn't a muscle or fat, which can be toned or worked away.... but there are ways to help tighten skin a bit, cardio, weights, diet and hydration are all big factors:
http://allwomenstalk.com/how-to-tighten-loose-skin-after-...
http://getfitguy.quickanddirtytips.com/how-to-tighten-loo...
http://www.fitnessthroughfasting.com/loose-skin-after-wei...