A hard lump on the left wrist that hurts may be tenosynovitis, which can be relieved by exercise, oral medication, or surgery. 1. Exercise: a hard lump on the wrist can usually be due to hold the mouse for a long time or poor posture, resulting in joint damage, and triggered by tendon sheath cysts. If the tendon sheath cyst is not serious, you can do some hand exercises to improve the symptoms, such as rotating the wrist, etc., through the movement can release the bad posture, promote blood circulation, so as to achieve the purpose of pain relief. 2. Oral medication: If the tendon sheath cyst in the wrist is more serious and the pain is more intense, in this case, you can follow the doctor’s instructions to take some oral pain medication, such as ibuprofen tablets, diclofenac sodium tablets, etc., to relieve the pain. 3. Surgery: If the pain is severe and affects the function of the joints of the hand, surgery is usually required. If you have any discomfort in your hand, you should go to the hospital as soon as possible to get a clear diagnosis and standardized treatment, so as not to delay your condition.