Welcome to the Health care Magic,
It appears that you have developed a disease called as Pilo Nidal Sinus
This sinus is developed in the inter gluteal region as hairs of that area scratch and make the area raw. finally this raw area gets infected and that is the beginning of the sinus.
It requires proper cleaning and dressing regularly along with relevant antibiotic.
If this does not heal conservatively. then finally surgeon takes care of that place.
So please it requires proper consultation.
Hope your query is answered