hi. noted history of small black lump on your breast. based from your description, it may be a sebaceous cyst formation. other breast lesions, such as fibroids, fibrocystic changes, tumor lesions and/or lipoma (fatty deposit), must also be ruled-out. it is best if you consult with a doctor, preferably a general surgeon, for physical examination and clinical evaluation. breast ultrasound and/or mammography studies may be suggested for further evaluation of the lesion. management (medical and/or surgical if indications are found) will be directed accordingly. hope this helps. good day!! ~dr.kaye