It's possible that this is the problem.
Try soaking the snake in a tub with lukewarm water that goes about halfway up the snakes sides for about an hour. Then let the snake slither through a damp washcloth to try to work the shed off.

In the future, when your snake turns blue before a shed, you should up the humidity to 70%, or make it a humid hide. That should help the shedding process along much more smoothly!