Hello,
From the symptoms since this rash is non itchy, so it can be due to dermatitis skin or contact dermatitis. I sincerely advise you to consult a dermatologist and get yourself evaluated for these possibilities.Till then, you should keep the area clean, wear lose comfortable clothes to avoid sweating, use a powder to keep the area dry and use calamine lotion at the sites. Oral antihistamine medications would help if the lesion is itchy.
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.
just wanted to add that it has been about 2 weeks since I originally noticed it