What I'd do first: I'd wait to feed him if at all possible (he's not starved, is he? we aren't seeing him...) BECAUSE the handling you'll be doing to get rid
of mites may cause him to barf up any food you give him right now anyway. He'll be a little stressed but he can live without a meal or two, whereas if
you don't treat the mites, they CAN kill him. OK? Mites need to be dealt with A.S.A.P.
Get rid of his cage decor (sorry but mites can survive there & get right back on)...it's toast. White paper towels (or napkins) only are best so you can see
the mites...and they can HIDE in other substrates. Thoroughly clean his cage before you put him back in (after his bath>>>).
Soapy water (mild soap like Ivory for dishes) will drown most of the mites on his body, but you MUST* supervise him for 20 minutes or so, slightly warm
water & not too deep (no deeper than his body thickness). Mites on his face will survive though, you cannot soak his head (!) but try to wipe his face at
least to get any that you can. Then gently dry him off & return him to his cleaned cage. (*Make sure he doesn't drink any soapy water*)
You can (& should, IMO) bathe him daily while you wait for "PAM" (that's "Provent-a-Mite" spray) to arrive. You'll have to order it, I'm sure, so don't wait.
When you get the 'PAM' follow instructions exactly...it can be toxic (even fatal) if used incorrectly...but many here have used it successfully...read some
threads on "how-to" while waiting for yours to arrive.
I'd personally not use Frontline on a snake, esp. not on a baby...easy to get too much & it's NOT designed for snakes. I would not risk it.
Can't comment on your reptile spray, no idea what's in it or the directions.
sorry you have to deal with this....mites suck!