Local redness, swelling and pain may appear within 2-3 days after tooth extraction, which is a normal phenomenon. If the pain does not ease or even gradually increases after 2-3 days, there may be secondary infection. At this time, you can see obvious redness and swelling of the wound, swelling of the lateral part of the extracted tooth, swelling of the mandibular lymph nodes or (and) lymph nodes behind the ear, restriction of mouth opening, or accompanied by fever, bad taste in the mouth, or even pus overflow, etc. You should seek medical examination and symptomatic treatment in time. Under normal circumstances, the wound surface should be covered by blood clot for 2-3 days after tooth extraction, and granulation tissue should be gradually generated, which can completely cover the wound surface in about 7 days. In case of acute infection, dry socket can be formed, which shows that the socket is still empty at 7 days after tooth extraction, or there is grayish white material with foul-smelling necrotic material, and in serious cases, it can also lead to the exposure of the bone surface of the tooth bed, accompanied by obvious pain, and the pain radiates to the neck and ear, which cannot be relieved by taking painkillers. In this case, it is necessary to promptly seek medical attention to remove the local purulent tissue from the alveolar socket, disinfect it with iodophor or hydrogen peroxide, and use antibiotics for anti-inflammatory treatment to prevent the infection from extending to both sides and spreading to other healthy teeth, making treatment more difficult and burdening the patient’s own health. In addition, the occurrence of infection is also related to improper care after tooth extraction, so it is necessary to avoid brushing, rinsing, repeatedly sucking or licking the trauma within one day of tooth extraction. After a day until the wound heals, you need to disinfect the wound in time and use mouthwash as prescribed by the doctor to prevent the growth of bacteria. You can choose light, easy-to-digest and easy-to-chew food, such as noodle soup, and avoid spicy and greasy food, tobacco and alcohol to cause oral discomfort. If infection has already occurred, prompt medical treatment should be sought to promote the healing of the alveolar sockets.