Welcome to Healthcaremagic forum.
Yes you are most probably suffering from fungal infection
( tinea cruris
The topical antifungal
treatments ( like hhzole) might only temporarily improve the infection but cannot cure it .
You have to take a course of prescription antifungal tablets ( like terbinafine or fluconazole ) .
So please do not neglect it and consult your dermatologist
( skin specialist ) who can confirm the diagnosis & start treatment for complete cure.
Wishing you good health .