Lump after mastectomy

Hello

I've had mastectomy a year ago and have an expander. I was on waiting list to swop the expander to implant,  one year down the line finally got to the top of the waiting list. (Meant to wait 3 months but such a backlog ..) just before my consultation I found 2 pea sized lumps right next to each other on the upper breast. Surgeon said its part of the expander and he isn't worried. It must be the port of the expander. I responded, it wasn't there in the past 12 months . He then gave in and arranged a scan. I had the ultrasound today and they were concerned enough to do a biopsy . Obviously it wasn't part of the expander. I will have to wait 10 days now. Does this mean cancer came back? 

Floored..

Has anyone been in similar situation.and what was the outcome.

Thank you