Post Breast Reduction and Brown Nipple Discharge?

Hello, I'm 12 weeks breast reduction post op, and my right breast still has a few hard swollen spots. Today they started to ache and then I noticed that the nipple had brown discharge. I have had that breast drained at my 6 week appointment but not since. Is this a seroma and will my body just take care of itself? or is this something worst and I will have to go back in to have it looked at. thanks note: I had almost 10lbs removed between both breast. This side was worked on the most