I had a similar problem about a month ago.
Follow these steps:
-take everything out of his/her cage and clean everything.
-change out your current substrate for Viva paper towels (there a little more expensive but the best)
-make sure the water dish can't be knocked over and until the scale rot clears up don't worry too much about humidity. The goal is to keep the snake clean and dry.
-get a triple antibiotic ointment (make sure it doesn't have a pain killer in it).
-put the ointment on once a day and just monitor it.

Make a call to your vet just to get him/her checked, while it may not be a severe case it doen't hurt to get them looked at.

You should be fine if you follow these instructions.
Cheers