If you have foot calluses, you know how aggravating and unsightly they can be. Calluses on the feet can make walking extremely painful, and they can also hurt when shoes or socks rub against them. Foot calluses are small patches of rough and discolored skin and although they can develop on the feet, they are common in other parts of the body too; if you use tools or play a musical instrument, you may get calluses on the hands. A callus on the sole of the foot can be especially painful and is known as a plantar callus. A callus is not the same thing as a corn, although people tend to lump them together, and corns can be just as annoying and as painful.