Is it normal to have a bruise on your penis?

it all started about 4 months ago when i was running from something and i stepped on a lawn chair. the chair somehow sprang up and nailed me right on the tip of my penis. it hurt because i got hit in the privates but the tip of my peis didnt hurt. so i went home and saw that at the fip of my foreskin, i had a bruise about the circumference of a small pea. and its been there for 4 months or so. it doesn't hurt at all, but its not really going away. i dont know if its serious, if i should just let it very slowly heal? help!