A suddenly swollen and somewhat hard chin can usually be caused by the following: 1. It is possible that the inflammation is caused by an infection in the soft tissues of the chin. It is common to see folliculitis, acne, or inflammation of the soft tissues around the chin, such as inflammation of the gums, which may also lead to swelling and hardness in this area. 2. It may be caused by swelling of the lymph nodes in the chin. In addition to the local hardness, there are also granular things on the chin that can be felt and painful when pressed. In addition, it is accompanied by symptoms of upper respiratory tract infection, such as dry throat, sore throat, cough, coughing, nasal congestion, and runny nose.