Hard lumps in the chin may be caused by trauma, swollen lymph nodes, epidermal cysts and other factors. 1. Trauma: If you accidentally bump or touch your chin, it may lead to subcutaneous bruising, resulting in symptoms of swollen and painful skin. 2. Enlarged lymph nodes: Inflammatory reactions such as upper respiratory tract infections and sinusitis may cause enlarged lymph nodes, which may lead to the formation of hard and smooth localized lumps on the chin. 3. Epidermoid cysts: trauma and other factors lead to epithelial squamous cells implanted in the subcutaneous cysts, usually manifested as hemispherical bulging mass, hard, elastic, mobile, slow-growing, can occur in any part of the body. If you are not sure of the cause of the hard lumps in the chin, you should go to the hospital in time to get a clear diagnosis of the cause of the disease, and then carry out targeted treatment to avoid delaying the condition.