Does it matter if I stay on FaceTime all night? Will it harm my iphone?

Me and my friend are staying on FaceTime all night we will both fall asleep, it won't harm my iPhone 5c will it?

It's perfectly fine. Only one problem is try to avoid your phone to overheat - this could happen by leaving the screen on for a long period of time, and leaving it under somewhere like a pillow or blanket.

No it won't. You won't have any battery after! That's all! But just don't plug your charger to your phone while you're FaceTime-ing with you friend. It'll damage the battery.

Of course it would. Your iphone 5c will not last as long the way you used it. LIke everything else, the more you used, the shorter its life span.

The battery life would be going down fast and it may cause overheating