What causes an ingrown toenail?
An ingrown toenail can have a number of different causes. Cutting your toenail too short or rounding the edge of the nail can cause it to grow into the skin. Wearing shoes or socks that don't fit well can also cause an ingrown toenail. If your shoes are too tight, they might press the nail into the toe and cause it to grow into the skin.
You can get an ingrown toenail if you hurt your toe, such as stubbing it. This can cause the nail to grow inward. Repeating an activity that injuries the nail, such as kicking a soccer ball, can also cause an ingrown nail.