There are several common clinical reasons for the presence of small hard lumps in the armpit: First, the proliferation of neurofibromas in the soft tissue of the axillary skin can be manifested as small hard lumps with clear borders and still movable, and because neurofibromas are benign lesions, close observation can be taken when the volume is small. If, in the course of observation, the fibroma gradually increases in size and is accompanied by painful symptoms, the patient is advised to undergo surgery to remove it. Second, the blockage of hair follicles in the axillary skin, accompanied by local bacterial infection, can cause sebaceous cysts and infection, and the patient can also show a small hard lump with a hard texture, accompanied by redness, swelling and pain of the skin. In this case, vital iodine gauze or Ruyi Jinhuang cream can be given for continuous external application to promote faster absorption of local inflammation and avoid progressive aggravation of infection of small hard lumps. If the sebaceous cyst is accompanied by abscess formation, abscess incision and drainage should be performed and anti-infection treatment should be strengthened.