Hi there, Thanks for your query. You have apparently a perineal abscess (a large boil near the anus); the infected material has liquefied into pus. The abscess has burst, releasing the pus. In the background of chronic constipation, friction by hard stools cause bruises in the delicate anal lining, through which infection penetrates into the surrounding tissues (inner part of butt cheek) or even form a fistula communicating between the anus and the abscess. Consult your doctor and apprise him of my opinion. I am certain that he will agree with me. He will examine you to rule out fistula formation; put you on antibiotics and anti-inflammatory drugs; if required, he will give a small nick to completely drain the abscess. If you find my response helpful and informative, do not forget an “excellent” (5-star rating) to my answer, to ENCOURAGE ALL doctors- engaged in social service- to render sound advice to the FREE queries. Take care Dr. Rakesh Karanwal