Whatever works. Watch & see what he does- if he doesn't make good use of it, you need to be more involved. You could literally wrap him up in a damp towel & let him rub against it for a while (while you hold the towel with him inside), but he probably won't stay in there if left to his own devices. A humid hide in his cage from now on would probably be a good idea, so he uses it before he gets stuck like this. Once their old skin get stuck on (so it's wrinkling & all) they need more help from you with a damp towel or a soak.
I think you'll find that in the future, it helps to pay attention to when his eyes go cloudy- that's when you want to make sure his cage humidity is about 70% until he sheds, which can be a week or more.