One possibility can be impetigo. It is a highly contagious bacterial infection and causes blister like sores on the body.
Primarily caused by Staphylococcus aureus and sometimes by Streptococcus pyogenes. Topical and oral antibiotics are the treatment of choice. My sincere advice would be to consult a dermatologist and get them prescribed.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.
I am experiencing the same rash. It appears at the base of my neck where it meets the shoulders on both sides and on the back of my neck. Three doctors have viewed the rash and all told me that they have never seen any rash like it. I have a suspicion that it is surgical mesh that has broken loose from a previous surgical procedure. Doctors don't like to say anything that may involve another doctor. Last one suggested I have a biopsy of the area when pattern is there (it comes and goes). This will be my next move. I will let you know what happens but it may take a while. I have tgo make appointment and then hope rash appears for same.
I read the Doctor's answer to you question. Good luck trying to get some answers. It's a crap shoot as far as I'm concerned. I have been having problems with this rash for about 2 months.