Hello dear, I can understand your concern, we ll it is not sexually transmitted disease, although affect the private parts, I think you should take higher antibiotics like amoxicillin plus clavulinic acid, or get done pus culter sensitive to know which antibiotics will be help ful.keep the area clean by cleaning it with Luke warm water, and apply fusidic acid cream twice a day, another thing is keep in mind hidradenitis suppuritiva , a condition similar to boil but it s a chronic condition and affects the axillary and groin area, it s because of obstruction of apo-ecrine gland duct. do consult a doctor to get the medicines prescribed, thank you