What happened is your humidity is too low and your tank will need some modifications to help with that.

For now here's what i do with stuck sheds....

Sterilite tub with lid no holes
1 to 1/2 inches of 85 degree water
Towel in the bottom of tub for the snake to rub on
A half log hide is good for one thing, helping snakes shed
Adding one helps them rub that old shed right off.

Soak for 30 minutes and replenish with more 85 degree water for 30 more minutes.
After that the shed should slide off easily.
Make sure when you help it off that you pull from the head towards the tail

When you get to the tail make sure your over a towel or something that cleans easily, they tend to dump their load when the shed comes off of the cloaca.
Trust me when I say you don't want to pull the shed off with the snake over your lap