You have to suffocate the mites. It does nothing to just clean his tank. The mites will be on your snake. To do this, you need mineral oil. Slather your snake in it but avoid heat pits, nostrils and eyes. Leave him be in the mineral oil for 30 minutes and then soak him in some warm water for about 15 minutes making sure all of the mineral oil is off. Do this daily until all signs of mites are gone. Aslo, cleaning his tank would be the first step. You need to bleach his cage and let it air out for 2 days before lining it again with substrate and basically letting your snake live in it again. Do not put your snake in his usual enclosure until all signs of mites are gone. You need a temporary housing for him, plastic tub is the better option here. A hide, heat source, paper towel and a water dish. That is it. Bleach his cage with hot hot water, also his accessories like hides, water dishes, any decorations and throw out the old substrate. Letting these soak in hot water for a few hours never hurts. Then you need to vacuum the room, (couches if in the living room) wash bed sheets if in a bedroom. Anything fabric these little things can hide in. Usually they do not hide far from the reptile though. Catching mites early on does not mean an easy battle. Good luck.