After a toothache, there is a hard bag in the jaw, which is usually an abscess in the periapical area. 1. Pulpitis or chronic periapical inflammation fails to carry out root canal treatment in time, the infected material in the root canal fails to be removed, and the pain is temporarily alleviated after being controlled with medication, but when the body’s resistance decreases, bacterial secondary infection causes an acute attack of chronic apical inflammation, which produces pus in the periapical tissues causing severe pain. 2. Along with the development of the disease, the periapical alveolar bone suffers damage, the pus spreads to the surrounding tissues, the pain is reduced, and an abscess is formed at the root tip, producing a pustule. There is a situation in which a pustule is produced in the jaw after a toothache, and it is necessary to go to the stomatology department for root canal treatment. There is a hard bag in the jaw after a toothache, and there is also the possibility of local lymph node swelling caused by inflammation, it is recommended to seek medical attention in a timely manner, under the guidance of the doctor to check and treat, to avoid delaying the condition.