Welcome to the forum, Rosebilly95!

Yeah, changing his bedding should take care of your humidity problems. Aspen doesn't hold humidity very well. Try using cypress mulch or a coconut-based substrate instead, like Eco Earth or Reptichip. Use at least two inches of substrate, though three or even four would be better. Adding an additional water bowl or switching out the one he has for a larger one can help as well.

What kind of enclosure are you keeping him in (glass with a screen top, PVC, wooden, etc.) and what kind of heat source are you using (CHE, RHP, UTH, etc.)? Some enclosures hold humidity better than others, and CHEs can dry out enclosures.

And good on you if you've kept Deadpool for most of those ten years. It's nice to see people stay dedicated to their snakes!