Finger long a hard lump may be callus, may also be common warts, skin cysts and other diseases. 1. callus: also known as callus, callus occurs mainly with the hand long-term friction or pressure and other mechanical stimuli, making the local cuticle overgrowth, mostly in the fitness, often playing musical instruments and other people. The main manifestation is that the skin of the hand is thickened and rough, and there is a hard bulge, which can be mistaken for a pimple, and it is usually yellow or wax-colored. 2. common warts: this disease is mainly caused by the infection of human papilloma virus, which can be transmitted through indirect or direct contact. Common warts are found on the hands and appear as hard pimples with a rough surface, usually grayish brown, brown or normal skin color, and can appear as hard bumps on the fingers. 3. Skin cysts: the cause of this disease is not yet clear, research has shown that it may be related to heredity, trauma, sebaceous glands congenital developmental abnormalities and other reasons. As there are more types of skin cysts, the clinical symptoms vary from person to person, so some patients will have hard lumps on their hands. To summarize, patients with a hard lump on the finger need to go to the hospital to improve the examination, to clarify the specific causes, and cooperate with the doctor to actively treat the original disease.