It is better you consult a qualified chest physician who can do appropriate investigations as well as physical examination and suggest you the next course of action. no signs of recovery may be due to unidentified drug resistance,or disease caused by multi drug resistant bacteria, Poor drug penetration into the lymph node, Unfavourable local milieu, Enhanced delayed hypersensitivity reaction in response to mycobacterial antigens released during medical treatment of the disease.the dr can take decision whether your sister requires surgical aspiration or resection of lymph nodes in this kind of symptoms.patients immunity should be enhanced with proper diet and maintaining cleanliness of wounds by cleaning and dressing them with medication regularly.