Luckily I've only had one dog get a hot spot(10 years ago) and it was due to a wasp sting to his cheek. It flared up and got ugly fast. I did not shave it and it responded well to Benadryl, Ceph(because it was pussing) and cleaning gently with Betadine and dabbing dry. Keeping it dry is the MOST important. You want it to scab somewhat and heal. Of course they want to rub it if it's on the face like my guy had, but he was actually very good about it and no need for E collar. I would try the cider vinegar if it happened today. Do avoid antibiotics as much as possible.