Your snake has mites. The most typical type of snake mites are black, but there are several hundred species that can potentially infect reptiles and many are red.
If you use aspen as a substrate you will occassionally get batches with wood mites. These are longer, thiner, and tan colored. They are nothing to worry about.
Mites on captive reptiles must be treated. In a best case scenario they cause dull scales, shedding issues, and are extremely uncomfortable and itchy to the snake. In severe cases (which is where most untreated cases go) they can cause anemia (they drink blood), dehydration, and death.
I have found that the best treatment for mites is a combination of "Provent-o-mite" and "Reptile Relief". There are generic brands of these products that are cheaper, and I am sure that many keepers will vouch for them, however I have seen other products hurt snakes (especially juveniles) so I stick to the stuff made specially for reptiles.
There are other home remedies that always get mentioned but don't really work that well. Soaking in olive oil to suffocate mites...no pest strips...etc. I have had great success using the two products mentioned above and I recommend them frequently to clients at the vet clinic I work at.
Follow the instructions to the letter and you should be all set. I would remove all substrate and go with paper while treating. Make sure you treat the entire area around the cage, and assume that any other reptiles in the house are infected and treat them too.
Cheers
