What Does A Painful Bump Around The Anus Indicate?

Hi, I am male 40 years old, I had an exposure with another male who I am used to connect with him, a day after exposure I found out a small bump (which I was guessing it may be a blister) in the age of my anus, it is kind of painful, I was trying to pop the bump but once I did, I saw a dark blood coming out of it, so I understood that is a blood blister, I didn t make full pressure to clean up the bump, so then I cleaned it up and put a alcohol pad over on the bump for few minutes to prevent of any kind of infections from bleeding. I am kind of worried now, he bump does not have any color, it is kind of skin color maybe a little dark, but I can feel the bump when I am touching or washing myself, would you please let me know what can be that bump? any advise to get rid of it quickly? Thank you very much