change to paper towels as substrate, and give the snake a nice soak in lukewarm water (not too warm or the snake might freak out). with one drop of dishwasher fluid per gallon of water, so the mites drown faster. a hint of soap is enough for that.
this will drive down the number of mites and provide relief for your snake until PAM arrives. killing something like 99.5% of the mites is not enough to eradicate them, but it definitively buys you enough time.
unless you have other reptiles and there is a risk of the mites spreading, there is no need to panic or rush things. i see no need to spray anything on the snake. PAM can eradicate the mites without anything ever being sprayed on the snake or the water bowl.