If there are still pieces of shed on the snake, I would get them off now by using the pillowcase trick. Put the snake and a damp towel in a pillowcase and put the pillowcase in the tank and let the snake chill out over night. I have NEVER had shed still on a snake after using that trick.
You might just invest in a moist hide if he has trouble even with good humidity. When the snake goes blue, up the humidity in a place where the snake likes to hide out. He's forced to be in a humid environment which will help the shedding process!