The wart subsides and disappears due to the action of the body's immune system. Untreated, plantar warts may grow up to an inch across and spread into clusters. A painful scar on the sole of the foot can pose an even more severe problem, which is why surgery is not the first choice of treatment. Many of these viruses die within 1-2 years, and the warts they produce simply disappear. While they last, though, the warts are ugly, irritating, and often painful.
Warts can grow back.
This indicates a virus is still in the body and growing. However, this is not cause for undue alarm. The virus that causes plantar warts is relatively harmless and causes few problems. Warts can spread to other parts of the body, particularly if scratching a wart causes it to bleed. Blood from a wart contains the virus and can cause a new wart to grow in an area that it touches.