It's not ingrown nails.
A friend of mine has a relative who is a missionary in Eastern Europe. He recently shared photographs and the story of a man he is caring for, who has an extremely bizarre skin condition. The man has keratin-like matter growing out of the skin on hands and feet, which started when he was young, and very slowly continues to spread and grow. The areas begin as skin lesions, and the matter sprouts from those spots. The growths are very difficult to remove, and the man has so far just had to learn to live with it. There are a few medical precedents to this man's case, but nothing is certain until more tests are done.