Is Slightly Raised, Dark Spot At The Base Of Penis Caused By Shaving Penis Scrotum Area?

A dermatologist found a dark spot at the base of my penis. He said it was slightly raised when he closely examined it, so he froze it off. He said I may have gotten it from shaving since I shave my entire penis scrotum area. He didn't seem to be too worried but I'm a little worried. At first he thought it was a wart but then changed his mind. What could it be and should I be worried?