By asking the buyer's doctor, I know: Pain: If you rub this acupoint with great force, it will stimulate the skin, nerves and epidermal muscles, and make the patient feel tender locally. Red swelling: Rubbing Zusanli for a long time will cause swelling of the skin surface due to excessive friction of the foot skin, which will stimulate the skin and cause redness. Congestion: if the subcutaneous capillaries are destroyed vigorously, it will lead to capillary damage and congestion under the skin.