Severe pain, emptiness at the extraction socket, or a strong putrid odor 2 to 3 days after extraction generally suggests that dry socket syndrome may have occurred, as follows. 1. Dry socket is a post-extraction complication that pathologically manifests as osteitis or mild limited osteomyelitis of the alveolar bone wall. Dry socket usually has severe pain 2~3 days after tooth extraction, and radiates to the top of the head, ear temporal area, jaw area, general pain medication can not stop the pain. 2. Clinical examination shows that the blood clot decomposes, destroys and falls off, resulting in emptiness in the extraction socket, or the blood clot is corrupted and denatured, with a strong putrid odor. If the above symptoms occur, it is recommended to go to the hospital in time for early professional treatment.