Hello and welcome to healthcaremagic
I would keep a possibility of fungal infection/
tinea cruris. Body folds, specially groin, axilla, submammary folds are a common site of fungal infection, specially in hot and humid weather. Clinically fungal infection commonly presents as red rings with central clearing and peripheral spreading and scaly rim.
Closely opposing body folds can trap sweat, heat and moisture, therefore making the area favorable for fungal proliferation.
If I was the treating doctor I would have asked to use a
topical antifungal like clotrimazole/sertaconazole/luliconazole cream, twice daily, regularly for 4 weeks.
An
oral antifungal e.g
fluconazole once every week for 4-6 weeks OR
Terbinafine 250 mg once daily for 2-4 weeks, is also advisable.
An OTC antihistamine e.g cetrizine syp, once daily would help in symptomatic itch relief.
regards