Ingrown toenails are a common condition in which the corner or side of a toenail grows into the soft flesh surrounding it. It most commonly occurs on the big toe. Symptoms include pain and tenderness in your toe along one or both sides of the nail, redness around your toenail, swelling of your toe around the nail and possible infection of the tissue around your toenail.
Often you can take care of ingrown toenails on your own. If the pain is severe or spreading, your doctor can take steps to relieve your discomfort and help you avoid complications of ingrown toenails.
If you have diabetes or another condition that causes poor blood flow to your feet, you’re at greater risk of complications of ingrown toenails.
See your doctor if you experience severe discomfort in your toe or pus or redness that seems to be spreading. Also check in with your doctor if you have diabetes or another condition that causes poor blood flow to your feet and you experience any foot sore or infection.
— Source: Mayo Clinic