I'm a 27 year old male.

Back in 2004, I had an operation for multiple benign rectal polyps. Ever since then, I was asked to maintain a balanced diet, with plenty of fiber.

Recently (2008), after coming to UK, I suffered constipation for one week, and then an anal fissure, after which, I started bleeding from my rectum.

The bleeding went away, but now I am left with a white tender lump (pea-sized) outside my anus (no bleeding after defecation). It's been around for over 2 weeks now.

I don't know what the hell it is, but when I sleep or walk around, it disappears. However, as soon as I sit down or start lifting heavy things, it reappears. It's painful too - sharp pain.

To make matters worse, I smoke and the constant coughing seems to push out this lump every time it disappears.

I tried using Anusol Plus HC, but it didn't help at all. My doctor (back home who performed the operation in 2004) recommended an ointment (Nupercainal) which I know might work, but it is no longer available in UK.

I don't know what this white lump is, and why it reappears every time I sit down. What do you think it can be? Is there an ointment I can try that is available UK?