Maybe try switching substrates.
Cypress much holds humitidy very well. If you buy in bulk from a hardware store it can be quite cheap. You just have to be sure to bake the substrate in the oven to kill any unwanted bugs. Makes your place smell earthy but i kinda like it lol.

Other than switching substrate, if your worried about the humidity maybe just give your snake a moist hide, that will help when shedding as well.
A tubberware container with a hole big enough for the widest part of your snake filled with damp sphagnum moss. That will at least give the snake comfort until you can figure out a way to up the humidity.