Unknown, but shallow penis growth?

Hello, I only made this account because this issue seems relatively simple but I need a second opinion, though some might yell at me for not checking in sooner.

I’m in my early twenties and for some time now dating back to at least high school, I’ve has these two very small, almost follicle-sized growths in the shaft of my penis. Its dark brown in coloration (my skin is light, which is how I noticed it at first). 

Since I discovered it and bothered picking at it, I’ve managed to dig it out of my skin easily about 3-4 times over the years by just pinching the skin similarly to a zit: it doesn’t hurt, it’s not embedded very deeply, it doesn’t bleed when I dig it out, and it regrows in about a month or two whenever I leave it alone, without spreading. Closer inspection shows makes it look somewhat flat, with a little bit of tissue connected underneath maybe. 

I’m honestly not sure what it is. It didn’t immediately set off fire alarms in my brain and I figured maybe it was a birthmark. I’ve been checked for STD’s and I’m relatively healthy. Should I be worried? Does anyone have any similar skin conditions I don’t know about? 

Post a picture buddy, easier to get help then. But I would advise to not pick at them, coz you could potential damage the tissue which my cause more obvious marking like. I had a couple of bumps on my penis and they were confirmed harmless but I have actually made the tissue surrounding look worse because of my attempts at removing them