I would just wait, snakes have a tendency of doing these things on their own. If you can see the actual skin sitting there, not coming off; then I would say try rubbing it off gently with your hands again. I have had to do this before, it works pretty well. But since you say it isn't coming off, that probably means it isn't ready to come off. Just wait awhile longer. When you tried rubbing the skin off, did you start from the neck? It's most likely not going to work if you don't start from the neck, or the point in which the skin stopped coming off.

Jennifer