Well the mites did not come from spraying the tank, they were already there or they were actually wood mites from the bedding. You need to get your warm side temps up to about 92 and the ambient in the 80's you really need to watch your temps. The cold can cause a RI, and if all else fails get him to a vet, no one here will diagnose a problem since we can not see the snake. Warm him up and see how he does.