Pimple type structure in my penis shaft.

Hello doctor, I am a 22 year old, healthy fit man. Yesterday I found a single small shiny looking pimple like structure in my penis shaft, the small bump is slightly pale in colour comparing to the surrounding skin, especially the center of the bump is slightly white. It doesn't causing me any discomfort or pain. But whenever I press it, it pains slightly, not too much. Doctor, please tell me what is it ? Is it a tumor or cancer ? Is it an STI infection (But I never had sex with anyone till today, but I masterbate sometimes, 2-3 times a month) ? Does it go away on their own ? Please doctor tell me, the thing is worrying me. I can't concentrate on my studies, because of that thing. I am very much worried & terrified about it. 🙏