Re: slipped skin
Definitely not what I think is going on with this snake. I actually went back to the original image to double check that when you mentioned the scales coming off... The scales are much too large and normally placed. At least from my experiences with it....but I mostly saw it in very young snakes.
The snakes I had seen with chronic malnutrition all have the same look to them, skinny, super dehydrated appearance and heavy wrinkling around the neck where the looser folds are. The scales will be much smaller in comparison to a healthy snake and the spaces between the scales are very noticeable. I don't see this in the photos you presented.
The skin will sometimes crisp up and look like someone dribbled super glue on it before it will crack and expose the skin underneath. It's never just one or two scales, it will be a large gash. Handling the snake can make it worse as the pressure on the skin can cause cracks and seepage of fluid elsewhere that dries into that super glue look. Sometimes before the cracks you might see little bubbles here and there under the skin before it cracks. The skin feels like rough single ply tissue paper.
One or two scales falling off and exposing white skin definitely sounds more like a healing burn or the excessive mites. The area under one scale being damaged enough and not the whole area like you would see in a systemic example like slipped skin from malnutrition
Hope that helps as well!