Pick him up an look at him real good - mite are not hard to see - look around his eyes and pits if you see a bunch of tinny blck dots scurry around - you have mites. Or take a white papertowel and wipe him down - if hes got mites you'll see them on the towel.
To get rid of them:
1. Treat snake with Reptile Relief (use as directed).
2. Remove everything from cage, Throw away old substrate, and anything that can be replaced. Thoroughly clean and disinfect the cage and accessories - be sure to give the corners and any crevices a lot of attention - this is where eggs might be laid.
3. When cage and accessories are clean and dry put down newspaper as substrate and include all accessories except water bowl and then spray cage with Provent-A-Mite.
4. While you are taking care of the cage - give your snake a good soaking in lukewarm water just deep enough to cover him where he can sit in the bottom and not have to swim.
5. When PAM is dry - you can put the water dish in and dry off your snake and put him back in the cage.
If the infestation is bad there is a good chance that you could have been spreading the mites around the house without realizing it - treat the surrounding areas of the cage and any areas the snake frequents with PAM. Make sure that you repeat the PAM treatment evertime you clean the cage and once a month at a minimum for a month or two - to kill off any eggs that you might have missed.
Hope it's just bark - if not best of luck!
-----
Tosha 
"Nihil facimus sed id bene facimus"

11.42.0 Ball Python (Harry and Fluffy and gang)
1.0.0 Angolan Python (Anakin Skywalker)
0.0.1 Green Tree Python (Verdi - yeah I know but my kids love the book)
0.1.0 Bredls Python (Smurfette)
0.2.0 Feline (Pippen and Pandora)
0.0.1 Desert Tortoise (Pope John Paul aka JP )
2.2.1 Fish (1,2,3,4)
0.0.0 frogs rescued from pool skimmer