Hi, I have a hard callous- like spot on the ball of my foot, right below my big toe, and about 5 years ago, I stepped onto a toothpick and no one noes if it is still on there( it was a small piece). Now five years later, the spot is becoming infected with thick yellowish-clear puss. It will seem as though it has healed, but when the scab Is pulled off puss will drain. And then it will look like there is a small hole in my foot surrounded by layers of dead skin. What is this and how can I treat it?