A hard lump by the chin can be recommended for an ultrasound to get a preliminary idea of the source of the lump. Ultrasound is not radioactive to the body, so you can start with ultrasound to see if the hard lump by the chin is one of the more common lymph nodes. The more common hard lump by the chin is usually a reactive lymph node hyperplasia caused by inflammation. For example, when the human body has respiratory infections, especially upper respiratory infections, dental caries and gum inflammation, they all tend to lead to reactive lymph node hyperplasia in the neck, which manifests as a hard lump by the chin. If the lymph nodes may be derived from other malignant tissues by ultrasound reaction, it is recommended to combine this hard mass with a puncture cytology examination if necessary to further determine the nature. Usually it is an inflammatory mass and can be treated with antibiotics. In the case of masses of malignant origin, the primary lesion needs to be found.