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.Application of local antifungal cream(terbinafine, clotrimazole, econazole, ketoconazole, miconazole) and oral antifungal drugs are the mainstay of treatment.
If still the symptoms do not improve then pls get a clinical examination done by a dermatologist. Intertrigo has to be probed.
I hope that helps. Please do keep me posted on how you are doing or if you have any additional doubts.Warm regards.