Hi and welcome. If your wondering what it is we cant diagnose here as would only be guessing. Sounds like an inflamed hair folical. If your worried maybe have a doc check it out esp if your sexually active.
I got tested for HIV, Chlamydia, Herpes, and another test(forgot the name) I am clean. But it kinda does bother me I didn't tell the doctor I had a spot on Penis Shaft I feel like going back and telling him. I don't know why I hesitated. The spot has not changed, Also I looked up Inflamed hair follicle and I saw a pimple like thing with red around it. I don't have red around it.I also have not got anything else it just that one little thing. I may make a new appointment because I feel uncomfortable for future relationships.with this little spot.