Patient: I am a male, 24 years old. 4 days ago, I went to the hospital to have my right maxillary wisdom tooth extracted because of shallow caries, because I have been smoking for more than 4 years, plus a small amount of calculus, the doctor gave me a scaling first and then the tooth was extracted. The extraction process went well and the bleeding was not too much. However, I went home at night with a low fever of about 37.3 and a headache. The next morning I woke up and found that my gums were a little swollen, the gums were dark in color, and there was a white film on the gums that could be wiped off. There were three white sores on the gum side of the extracted tooth. What is the cause of this? Doctor: First of all, tooth extraction is also a surgery, and there is a traumatic reaction process after extraction, which is usually local swelling, tolerable pain and low fever for some people, usually 2 to 4 days after extraction is the peak reaction period, and then gradually improve. The degree of reaction depends on the situation when the tooth is extracted. If knocking and splitting techniques are used, the reaction may be greater and take longer. The total reaction time after tooth extraction is usually one to two weeks, and any swelling and pain within one week can be considered as traumatic reaction, which can be treated symptomatically, such as oral pain medication, without too much tension. Serious infection rarely occurs after tooth extraction, unless the tooth is extracted in an irregular place and the extraction instrument is not sterilized and causes infection. In your case, I think it is still a traumatic reaction and does not need special treatment. It may be better to wait for two more days, as the peak reaction period has almost passed.