The correct term for the end tooth is the third molar. The extraction of the third molar usually causes continuous pain for about 2~3 days, and the pain time may be prolonged in case of post-extraction reactive pain, post-extraction infection, dry socket and other complications, as follows. 1. Post-extraction reactive pain: larger extraction wounds, the blood clot is easy to break down and fall off resulting in the exposure of nerve endings, which will cause pain when stimulated by the outside world. 2. Post-extraction infection: foreign objects such as bone fragments, tooth fragments and tartar remaining in the extraction socket may cause chronic infection of the extraction wound, resulting in pain. 3. Dry socket: Severe pain occurs 2~3 days after tooth extraction, and the extraction socket is empty or there are blood clots with corruption and degeneration. If the above symptoms occur, it is recommended to go to the hospital in time to receive early professional treatment.