I hope your snake is okay, but judging by your lack of response, I'm thinking it's not. If he dies (and I'm sorry, but that is a real possibility), you should have a necropsy done. If the report shows that it was permethrin poisoning or whatever else kind of poisoning, you should take that report to the shops that cleaned your snake. They need to be held accountable for what they did.

This sounds like the kind of reactions snakes can have when using lice spray or permethrin products not formulated for reptiles or not diluted properly for those who know how to use them (and anyway, those products are used to treat the enclosure, not on the actual reptile).

And since your other snake might have a mite issue -- You need to know that just cleaning your BP isn't going to get rid of mites. They lay eggs inside and around the enclosure, so you have to treat that as well. I recommend getting Provent A Mite. Remove the water and the snake, spray it as directed (it tells you how long to spray and how far away to hold it), wait for it to dry completely, and then put your water and snake back. Mites should be dead within three days. Reptile Spray that PitOnTheProwl posted rules as well for killing the mites on the snake (and can be used for cleaning the enclosure), but you will need something extra to kill the eggs.

We were all new snake owners once. People make mistakes. Good luck, I hope your snake makes it.