Patient: I have had a bump on the lower part of my penis shaft for about 6 months. It is usually colourless but can sometimes be red if irritated. At first i thought it was an ingrown hair because i had shaved the area but no hair is visible. I had been able to get very little amounts of puss out of it but not for a couple of months. It feels like there is something firm under the skin, but it does not hurt. I am not sexually active. What is it?