I've found my water pythons have bad sheds now and then too. They require a higher humidity and also being an aquatic python in the wild, tend to spend a lot of time in or around water.
I've got up to 3 water tubs in their enclosures, some under the heat lamp to try to raise the humidity. You have to cut down on the ventilation a bit more than usual too.
Mine usually don't bite when I help them shed, as if they know what I'm doing. Still got a female that is the spawn of satan though.