I was thinking the same thing Robin, most skin infections are staph
fungal so an antibiotic or antifungal injection/pill may help. Can
they scrape it and culture it to see whats growing there? When my
horse had scratches, I treated her with silvadene an ointment used to
debride and treat severe burns in humans since most of their
infections are staph infections it worked very well with the
scratches. It was very expensive but to me worth it as it cleared up
in a few days.