An ingrowing toenail happens when the sides or corners of the nail grow into the skin, this can feel as if you have a splinter, can lead to extreme pain, inflammation, and infection. If required permanent removal of the side of the nail can be carried out. This is classed as minor surgery under local anaesthesia using a chemical to stop regrowth. Ingrowing toenails most commonly affect the big toenail but can affect the other toes too.