Hello,
It can be due to dermatitis skin or eczema. Wash the area with fresh water. Do not use any cosmetic products at the sites. You can apply some calamine lotion at the rash as it will help in soothing the skin. Also wear cotton undergarments. Maintain hygiene and try to keep the area clean and dry, wear loose-fitting cotton clothing. Also use mild soap like dove. Avoid deodorant / cosmetics. If the symptoms persist then get a skin biopsy done from a dermatologist to confirm the diagnosis.
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.
the doctor has given the opinion.