"It's where a blood clot fails to develop in the tooth socket, or if the blood clot becomes dislodged or disappears. This can happen 3 to 5 days after surgery.
The empty socket causes an ache or throbbing pain in your gum or jaw, which can be intense like a toothache. There may also be an unpleasant smell or taste from the empty tooth socket. If you look into the socket, you might be able to see exposed bone rather than a blood clot."
The pain is intense!