Hard lumps in the breasts after returning to the breast may be caused by accumulation of breast milk, mastitis and breast fibroid, which can be treated by local hot compresses, oral medication and surgery. 1. Accumulated milk: This time you can follow the direction of the mammary glands, squeeze out the milk or use a breast pump to suck out the milk. You can also use localized hot compresses or localized massage to promote the discharge of milk. 2. Mastitis: It is also possible that the milk is not able to be discharged in time inside the milk ducts, resulting in the accumulation of milk, which can easily nourish bacteria and lead to the occurrence of some inflammation, such as acute mastitis. You can use benzylpenicillin, hydroxybenzylpenicillin and other drugs for treatment under the guidance and advice of the doctor. 3. Breast fibroma: Breast fibroma may increase rapidly during breastfeeding, seriously affecting life and aesthetics. The tumor can be surgically removed after breastfeeding. Breast hyperplasia and malignant tumors of the breast may also appear in the clinical manifestation of hard lumps in the breast after returning to the breast, it is recommended that the patient go to the breast surgery department of the hospital in a timely manner, according to the actual situation of targeted treatment.