Hello there...I can understand your concern. It would have been better if you had posted a photo of the lesion. But from your description it looks like you could be suffering from a furuncle. It can only be diagnosed after complete clinical examination. Conditions like pilonodal sinus also can occur in that area. So kindly consult a dermatologist for further evaluation. If it's a furuncle, you will need oral and topical antibiotics creams.