What is this skin rash even the vet is baffled?

my dog keeps getting this rash on the top of her neck they look like small blissters when they pop there filled with blood and pus they go away with antibiotics but come back when the corse is finished she carnt stay on antibiotics all the time my vet to be honest is useless just keeps giving her antibiotics any suggestions?|||wow babe you have me baffled with this one, I bred dogs and have never heard of anything like it. You say it is around the neck ? could it be just a simple allergy to the collar or the chain babe. Try leaving them off and see if it improves. Have you by any chance got a flea collar on the dog because quite often these cause problems.|||Could it be ringworm?|||take her to another vet,,,,,try getting blood tests|||First dry her pus with Heparsulf 30 The pet should be fine but if it still continues give your per Rhus Tox 30 twice a day and he/she will be fine. This what my doc gave my pet and he became OK.Homeopathic wonders!!