Hello. Thanks for writing to us at healthcaremagic
You seem to have fungal infection
of the groin along with post-inflammatory hyperpigmentation
It is always better to get it confirmed with a specialist/dermatologist
rather than using OTC product because OTC product may not be very effective
If you were one of my patient I would have asked you to use one of the topical antifungal
preparations e.g either clotrimazole or ketoconazole or sertaconazole
. Along with the topicals I usually also prescribe oral antifungals e.g either fluconazole or terbinafine or itraconazole, to my patients. Since these are available on prescription, therefore I would suggest that you seek an appointment with a dermatologist in your region
An OTC oral antihistamine e,g cetrizine 10 mg once daily would provide you symptomatic relief from itching.
Because you live in a region with humid weather, therefore, it would be good to bath twice daily and also use an antifungal dusting powder regularly in groin folds which would keeping the folds dry and be non-conducive to fungal growth.
Wear loose fitting clothes