Thanks for your query at DoctorSpring.com.
I understand your concern.
Are you sure you have a fungal infection? What are the symptoms? How does it look like?
If it is a fungal infection you are highly advised to get it treated instead of applying vinegar. Without antifungal creams, it will not resolve and will spread to the other parts and may be contagious. Twice daily application for a week is sufficient.
Hope it helps.
Feel free to discuss furhter