I think you've received some excellent advice. If it's an ear infection on the inside then definitely try the ACV/ Colloidal Silver mixture. Where the area is raw I would use coconut oil and a drop or two of oil of oregano. Both oils are very healing (antibacterial, antifungal, antiviral, antiparasitic)...plus the oil of oregano will take away the pain and itchiness pretty quickly.
Good luck with your pup....I hope he's feeling much better very soon.