I do not have any snakes.

I have one lizard with no mites on it/in the cage.

I am using permethrin in probably a larger concentration than what's in Provent-A-Mite. I believe permethrin is the active ingredient in Provent-A-Mite so this is just more concentrated I believe.

This might be why I'm able to keep my mice from being infected.

I believe the mites are tropical rat mites.