You need a thermostat for the heating pad. Your humidity is low because you are using a lamp, they suck all moisture out no matter how much you mist, it's very annoying. I would recommend getting a humid hide to compensate. All you need is a tupperware with a lid. Cut a hole in the lid and put some sphagnum moss (available at any pet store) in the bottom of the tupperware. Mist the moss and keep it moist, but not sopping, and your snake can retreat in there for her shed cycle. I had PERFECT sheds as soon as I introduced the humid hide, and mine will actually stay in there for the full duration of her shed cycle, almost two weeks and not move. For that reason, it is a good idea if the humid hide is not in the coldest part of the enclosure, but on the warm end, or at least in the middle. I also mist during the shed cycle, even if she is in the humid hide.

My snake's first shed with me was also in pieces. Drove me insane. If the last part of the shed doesn't come off on its own soon, you will need to soak her. There is a sticky on how to soak under the husbandry thread, I believe.