Gums swelling and pain three months after wisdom tooth extraction may be caused by infection of the leftover broken root or periodontitis, the treatment is to remove the broken root or periodontal treatment, as follows. 1. Remove the broken root: If the gums are swollen and painful due to the infection of the leftover broken root, the gums should be cut open and the location of the broken root should be explored and then removed. It can eliminate the inflammation and achieve the purpose of reducing swelling and pain. 2. Periodontal treatment: because of the neighboring teeth of the periodontal inflammation caused by swollen gums, should do periodontal treatment, specifically including gingival cleaning and subgingival scraping, to remove plaque tartar, to terminate the inflammation of the continued development of swelling and pain. There may be other reasons for swollen and painful gums three months after wisdom teeth extraction, it is recommended to go to the hospital in time.