If I go on a 2 week fast, but properly hydrate myself, will I end up with loose, excess skin?

No, but you're metabolism may slow down and when you do eat again, you may gain weight back quickly.

If I go on a 2 week fast, but properly hydrate myself, will I end up with loose, excess skin?
Nah, not in 2 weeks. It also kind of depends on how big you are and how much you end up losing.
Reply:i just came off a big weight loss, and have a done a lot of research into my excess skin, no matter what you wil get it, some excercise will help pull it back in, it will take time for it to go back to tight