I keep my bp's humidity at roughly 55%. She drinks water and is plenty hydrated. I soak her for a little bit each day during her shed cycle and she still sheds in about ten pieces. She gets everything including her eye caps off every time but it just comes off in pieces.
She was my first snake and I got her from a reptile only pet shop. The owner when I asked him about it said that BP's are notorious for bad sheds.
I saw a vid once off a guy trying to hydrate a sick snake with a dropper you could try that I guess. I'll try to find the link.
Here it is:
http://www.youtube.com/watch?v=mLmXS9U0R-g
Its worth a shot.