Treating for mites is not something you do for a day or two, it takes at least a month because eggs can remain viable for quite a while. People think they treated properly for mites because they stop after a day or so, only to find a (re)infestation weeks later. This is why the PAM/NIX treatments every two weeks work - you spray the enclosure, hides, and paper towel or newspaper substrate, and allow everything to dry before putting the snake back in. DO NOT TREAT THE WATER BOWL because you don't want your snake to drink the permethrin.
Repeat the enclosure/hide treatment after two weeks, and again two weeks later. Keep a supply of permethrin-treated paper on hand so you can replace it when the snake makes a mess. The permethrin residue will kill the newly-hatched mites.
Also this is some good reading: http://denardo.lab.asu.edu/publicati...snakemites.pdf