An ingrown toenail develops when the sides of the toenail grow into the surrounding skin. The big toe is often affected, either on one or both sides. The nail curls and pierces the skin, which becomes red, swollen and tender. Other possible symptoms include: pain if pressure is placed on the toe inflammation of the skin at the end of the toe a build-up of fluid (oedema) in the area surrounding the toe an overgrowth of skin around the affected toe (hypertrophy) bleeding white or yellow pus coming from the affected area