Hibernating or long digestion?

[sierrabravo]

I haven't had my ball python for more than two months, so I'm not exactly sure what he's up to. I can tell you this much though: every time I feed him, he would digest for exactly four days. I feed the same feeder mice I was recommended by the petshop, always live, always inside a cardboard box. Last time I fed him was about 8 days ago, and he's been inside his hiding rock since. I can see him when I take the top off the rock, and he curls up tighter and looks at me while he's breathing, so I know he's still alive. He has come out a few times, but only for maybe an hour each, then back into the rock or under the half-log thing I have for him. I have the heat lamp on during daylight hours, and I have a bottom-tank heater on the side of the tank (so the bedding doesn't absorb the heat before he does). He started to get dry, grayish spots on his body which are indicitive of imminent shedding, so I added a "wet-hide" tupperware with water. Temp is usually between 80-85 F and Humidity is 45-50.