Has she been playin rough with the other pup? As far as oatmeal bath...it's not required with nu stock but it wouldn't hurt. You apply nu stock every 3 days. Benedryl maybe? I'm not vet so really not sure what that is.I've never seen her messing with it so I can't say she's biting it and.yes that smaller one on her face is one too
nustock is making it worse possibly i wouldnt put more topical things on until you figure out the cause. If you treat the missing fur but not the problem causing it its kinda pointless. Id look into switching foods to grain free for now see if it helps or go get a skin scrape done at the vet. You could get allergy tests done but from what I hear those can be pretty pricey.Try some vetericyn stuff is awesome! You can find it at your local feed store to cut down on price vs a pet store. Most Pet stores only have small bottles for the same price as the larger bottles.
Could be food related, doesn't quite look like ringworm.