I have this red spot on my penis?

Hi. Im only 16 and have never had sex. It is on the base of the penis closer to the balls than the head. Basically, I think i was rubbing myself on my bed at an angle,,, and a day (or two cant quite remember) later there was a red spot.... it doesnt hurt or anything. But it may have been caused by the rubbing against the mattress. What should I do and is this possible.