Is this considered dehydration? Poor husbandry? Etc?

ProventAMite can be used as a precautionary method, I do it. If you look around their necks and face, this is were mites seem to hang out the most. Paper towels are the easiest method for finding and concealing mites. The little buggers stick out the most on them. Raised scales is pretty common with underfed and dehydrated boas. Don't sweat it unless it looks swollen and/or red and irritated around the raised scales. I wouldn't really worry till after he/she sheds for ya.