Gran's box

You wake after a wild night of partying to find that while you were wasted, for some reason you had a crude smiley face tattooed on your foot. You write it off as a lesson to never drink that much again. The next time you wake, however, you discover the face is now on your ankle, and it's not as crudely drawn. The day after that, it's on your lower leg, and it's starting to look more like a drawing of a real face. As it continues to move up and become more realistic looking, you wonder what happens when it reaches your own face.