A raised hard lump on the head may be folliculitis, sebaceous cyst, fibroma, etc.. 1. Folliculitis: an inflammatory skin disease mainly involving hair follicles, mainly due to bacterial infection of hair follicles in the scalp caused by the red pimples, hard, and accompanied by itching and pain. 2. Sebaceous cysts: mainly because of the sebaceous gland excretory duct obstruction, thus forming a cystic skin changes, is a benign disease, in most cases there is no obvious pain symptoms, if secondary bacterial infection, may lead to redness, swelling and heat pain. 3. Fibroma: the specific cause of formation is not clear, may be related to a variety of factors, such as genetic factors, hormone secretion, trauma, etc., easy to lead to local subcutaneous obvious hard lumps. A raised hard lump on the head may also be caused by other reasons, if there are obvious symptoms of discomfort, you should consult a doctor in a timely manner to identify the cause of targeted treatment or therapy.