A small sore spot developed on the ball of my foot...red with a black spot in the center. However, it is not tender to the touch (like I think a plantar's wart is supposed to be). The spot was not too far under the skin, and I was easily able to trim off the top layer of skin. Eventually I pulled out a coiled up black hair. The sore sensation stopped immediately, and the skin healed over. However, the problem recurred. I just pulled out a hair for the third time. I've read about "hair splinters", but this is recurring in the exact same spot, and the hair is coiled up...which doesn't sound like a hair that's been driven into the skin; it sounds like an ingrown hair. I am retired and do not work in a profession where I cut people's hair or am otherwise exposed to stray hairs. I do have a dog, but his hair is not curly, or as fine as the hairs I am pulling out of my foot.