A hard lump on the sole of the foot should be corns or metatarsal warts, as follows: First, metatarsal warts treatment can be used with a laser, you can use drugs to smear foam. Secondly, corns can be frozen with frozen liquid nitrogen freezing, or surgical scraping, liquid nitrogen freezing effect is better, the reason for this is mainly the foot cuticle repeated friction formation of excessive keratinization of the toes. Once produced to pay more attention, wear shoes, walk to minimize friction. Plantar warts are usually found on the toes of the feet, and those on the soles of the feet are mostly corns, which can be removed by liquid nitrogen freezing or surgery.