
Scrotal mange... Like, it specifically attacks and dwells on testicles?! Scrotes/whatever... Sounds vengeful.

I'd never heard of such a thing! You could probably frighten any man off the farm in future if you tell them such a thing has afflicted your ram. Could be endemic, rampant in the paddocks.... LOL! I'm joking.
My brother did once get a staffy/shar pei mix dog from an unfortunately ignorant breeder who kept producing litter after litter of congenitally blind dogs with follicular mange; we treated the pup successfully on both counts. We used unpasteurized apple cider vinegar as a wash for his coat, it killed the mange off. I forget the details but we also treated his diet, following the advice of the Juliette de Bairacli Levy books. Have always found her works highly relevant and useful, even with diseases modern science can't yet treat with any decent rate of success.