If they were black specs and moving, they were probably mites. Go to Reptile Basics, LLLReptile, The Bean Farm, etc. and order a can of Prevent-A-Mite. Once that comes in, apply it per the directions and that should clear up your mite problem. In the mean time, go to a pet store and buy "Reptile Relief" spray and apply that to your snake. That should clear up your problem.

Also, I would clean the cage, the hides, the branches, the water bowel, etc. and put your snake on paper towel for now until you can get the mite problem cleared up. Then, once it's cleared, clean everything again and sanitize with something like F10 or Chlorhexadine (you can also buy that when you buy your PAM).