These little, noncancerous developments seem when your skin is tainted with one of the numerous infections of the human papillomavirus (HPV) family. The infection triggers additional cell development, which makes the external layer of skin thick and hard in that spot. While they can develop anyplace you have skin, you're bound to get one on your hands or feet. The sort of mole relies upon where it is and what it resembles. Causes of warts HPV causes the unnecessary and quick development of ker...