Hello,
Without examination,it is very difficult to confirm a diagnosis,but it can be eczema,contact
dermatitis rash(allergic or irritant0,
seborrheic dermatitis ,fungal infection(ringworm) or psoriasis.
Wash your groin daily and then dry thoroughly by pat drying,not rubbing. A hairdryer is useful if you have hairy groins.The damp groin is an ideal site for fungi to multiply.Also wear cotton underwears and change them twice a day. and do not share other people’s towels.