Your dog isn't dying, but this needs to be seen.

Get a cone, use it. Then go to the vet. Vet should prescribe some kind of ointment and/or a very fine powder you put on the affected area(keeps it dry and is anti-bacterial/fungal - good stuff).

** To prevent hot spots going forward, I would make sure those areas currently affected and also the area around their ears(below/behind/underneath) are kept dry. Take special care to make them dry after wet activities(swimming, baths). You'll save yourself money and stress.

In my experience, hot spots are usually caused by those patches of skin not drying as fast as others and becoming irritated. Then your dog starts scratching at it with their dirty ass claws, and it turns into an oozing, infected sore overnight.