Pathology report after mastectomy

Hi! I’m 36F, diagnosed with ER+ PR+ HER2 negative, stage 3 (T3N1M0) bc in July. I finished chemotherapy in November and have had a mastectomy a few weeks ago. My pathology report has come back but I won’t receive an explanation from my doctors for another week. From the pathology report, it says that I still had cancer detected in the margins. When they have already taken out everything they can? What might that mean for my future treatment if there were no clear maritime found in my pathology report of the removed tumor and tissue? Is there anything left to remove? From what I understand, it was less than .1mm found in the margins…so not a lot but it wasn’t considered “clear”. Has anyone else had this reported after a mastectomy and did that effect your treatment moving forward?