The bruising of the blood vessels of the injection is caused by the blood vessels not being pressed for a long time to stop bleeding after the removal of the puncture needle, resulting in the formation of a subcutaneous hematoma due to the leakage of blood from the vessels. Subcutaneous hematoma can stimulate local inflammatory cell infiltration and cause pain. After this happens, hot compresses or physical therapy can be applied to promote the dissipation of local inflammation, and drugs such as Xylitol can be applied locally to improve pain and accelerate absorption. If the pain is severe oral non-steroidal anti-inflammatory drugs, such as ibuprofen or diclofenac sodium, should be given in order to prevent this condition from happening again. Prolonged pressure should be given during infusion for at least 10 minutes to stop the bleeding completely.