I have a small red rash between my thigh and scrotum. i tried putting hydrocortisone on it and it hasent helped what could it be?

Nothing serious: At your age an itchy rash in that area is either a 'contact' rash of irritation or a fungal rash. Usually relatively easy to differentiate on exam, but if all else is normal for you health-wise try Lotrisone (clotrimazole and betamethasone) cream followed by Hydrocortisone twice daily for a few days. If rash persists or spreads after 4-5 days contact your doctor.

Yeast Infection: This could be a yeast infection which could be aggravated by hydrocortisone. I would suggest seeing a dermatologist for evaluation and different prescription.