Blistering of the tooth root is an indication of chronic periapical inflammation, which is caused by decay, trauma or pulpitis without timely treatment. If the inflammation in the pulp cavity is not treated in time, the inflammation will spread along the apical foramen into the periapical bone tissue, causing congestion in the bone tissue, an increase in inflammatory exudate, and even the formation of granulomas, abscesses, and even cysts, which will lead to the appearance of a pus-draining sinus tract and inflammatory polyps in the gum of the corresponding apical area, causing repeated redness and swelling of the gum and the growth of abscesses there. In this case, root canal treatment should be performed on the affected tooth to completely remove the infected material from the root canal cavity, and the inflammation at the root tip will be gradually metabolized and absorbed by the body itself, and the abscesses at the root will gradually disappear.