Mole or a splinter please help!!!?

okay so about 4 to 5 years ago i was walking barefoot on a driveway nothing happened then i put my left foot in my shoe and i think it was a splinter and i cant remember much but i think i got most of it out but now theres like a brownish looking thing on my foot its not like round but it isnt like too different if i look under the light i see lines of my skin from the layers of skin but im not sure if it is a mole or not. i did try to get it out a few years back but i dont think it would come out or i didnt dig deep enough:/ i have been fine so far it hasnt bothered me but i just wanted to make sure im safe!!