The socket is the hole in the bone in your mouth where a tooth has been removed. After a tooth is pulled, a blood clot forms in the socket to protect the bone and nerves underneath. Sometimes that clot can become dislodged or dissolve a couple of days after the extraction. That leaves the bone and nerve exposed to air, food, fluid, and anything else that enters the mouth. This can lead to infection and severe pain that can last for 5 or 6 days.