You are suffering from Tinea infection ( Fungal Infection)
Next Steps
You need to take medications atleast for 1 month with regular follow up. You need to visit dermatologist for the same.
Health Tips
Keep your body clean & dry. Sweating will increase the fungal infection. Wear cotton loose fitting clothes & use regular talcum powder atleast 4 to 5 times for keeping body parts dry especially groin areas.Avoid using dettol or other chemicals.