Probably just because she's in shed...but to be on the safe side, I'd encourage her to drink water...it will help her shed anyway, & shedding can cause dehydration in
snakes. Dehydration can cause weakness & low blood pressure in most any creature, including us.
If she won't drink from a bowl put up to her mouth, you can also just mist her...many snakes will drink beads of water off their coils, just as they do in nature when it rains.