Sentinel lymph node biopsy armpit hard short time to consider the wound inflammation, long time to consider the incision after surgery local scar formation. Sentinel lymph node biopsy axillary hardness if the time is short the wound has not been removed need to consider local infection need to go to the hospital in a timely manner to let the attending physician to review the wound, and then according to the wound condition to deal with. If the time is long, consider local scar formation. Sentinel lymph nodes are special lymph nodes in the lymph nodes in the drainage area of the primary tumor, and they are the first lymph nodes through which lymph node metastasis of the primary tumor must occur. Sentinel lymph nodes in the axilla are the first station of lymphatic metastasis of breast cancer. Generally, in segmental mastectomy with sentinel lymph node biopsy, a small incision is made in the axilla and the sentinel lymph nodes are accurately removed and biopsied. There will be localized scar formation after the wound heals after the surgery, and usually it can return to normal in three to six months. Clinical appearance of armpit hardness, it is recommended to go to the hospital to let the doctor specific examination, and then the doctor according to the situation to decide whether it is necessary to deal with before.