25/m small puss filled bump 1/4 inch above anus comes and goes about 3 yrs now pops in about 3 days bleeds heals over can repeat in week or 5 months.

Likely fistula: Sounds like you have a fistula originating from an anal gland going to the perianal skin, need to see a colon and rectal surgeon ideally at a time it's draining.

Chronic sinus: This could be either a pilonidal sinus or a perianal fistula. Both conditions need surgical treatment. You should consider seeing a general surgeon or colorectal surgeon.