Corns are a common problem on the foot. They are a natural reaction to pressure as the skin thickens up to protect itself from that pressure. At some stage the process goes wrong and gets so thick that it is painful. There is a persistent myth that corns have roots that they keep growing back from when you try and remove them. This is like the analogy of plants that grow back from their roots if you chop the top of the plants off. That analogy has been applied to corns as they keep growing back, but they do not have roots to grow back from.
Corns are caused by pressure and a skilled podiatrist can easily remove a corn. The problem is that after the corn is removed if the pressure that caused it is still there then, of course, it is going to grow back. It grows back because the cause is still there and not because the podiatrist left a root there for it to grow back from. That pressure may be from a poor fitting shoe or from something like a hammer toe or bunion that leads to increased pressure on an area. If the corn is under the foot, then the cause is increased pressure on the spot where the corn is, most likely because of the way you walk.
The myth persists because they do come back, so its important to remove the cause at the same time the corn is removed. There is no root to be removed. This means that the pressure over the foot where the corn was has to be reduced or removed. This will involve issues like using better fitting footwear or the use of padding to get pressure off the area where the corn is. Sometimes surgery will be needed to the bone under the corn to remove the pressure. If that cause is not removed or reduced then the corn will come back, so it is easy to see where the myth about corn roots comes from.