Are you sure they are snake mites? Are they dark black mites that are crawling directly on the snake? In the heat pits, around the eyes etc.? Or are they lighter colour and crawing on the substrate, decor etc.? If they are the latter, they could just be wood mites, and they are not harmful to your snake. If they are the black ones that are parasitizing your snake, then follow the advice about the PAM.