I cannot confirm anything without examination but it can be contact dermatitis, allergic reaction, heat rash, sweat dermatitis or scabies. If the rash turns painful and forms blisters, then shingles has to be ruled out.
Avoid using any lotions and creams for the meantime. Use a mild cleanser with moisturizing properties like Cetaphil. Also use cotton clothes and change the clothes twice if there is any increased sweating. Try keeping the skin free of sweat as far as possible. If the symptoms still persist then you can apply mild steroid like dermacort. For the itching antihistaminics like Benadryl or Claritin can be taken.
If still the symptoms persist then get an examination done from a dermatologist. .
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.
Thank you for your time Mr. Kaur. The information was very helpful. I looked at the all possible rashes you mentioned but it doesn't look so serious. I will monitor it and use a cleanser and will keep you posted.