Sometimes the forced air used to heat homes in the winter takes humidity out of the air to the extent that it's difficult for a snake to shed. To remedy this, put the snake in an escape proof container (like maybe a plastic Cool Whip container) with a 1/2 inch of water and either a handtowel or paper towels.
The snake will crawl through the towel and through friction, be able to rid itself of the old skin. This combination of water and something damp to crawl through has worked well for me over the years.
You can leave the snake in the container for an hour or two and in most cases, you'll find it will shed out completely (if not, you can peel the old skin or simply give the snake more time in the container).
Good luck!
Tim

Third Eye