Poor guy! Glad you are so attentive to him - I'm sure he's more comfortable now. For a couple of my snakes that don't like moss mixed in with their substrate, I just put a bowl of damp moss into the enclosure to help maintain humidity, and/or add a second water bowl and/or add a potted plant or two (something sturdy like Pothos). Any one of, or combination of, those things has helped bump and maintain humidity for me.