Hello,
Without examination it is difficult confirming a diagnosis, but it can be eczema skin, fungal infection or contact dermatitis/ allergic reaction
. Use a mild cleanser with moisturizing properties like Cetaphil. Also use cotton clothes and change the clothes twice if there is any increased sweating
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. Applying calamine lotion also helps in soothing the skin.
If the symptoms persist then get an evaluation done by a dermatologist. For testicular evaluation, it is best to get a scrotal ultrasound done.
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.