Is This Fat Necrosis, Infection, or Deep Suture Abscess? (photo)

I'm 7 weeks post bilateral breast reduction. Since post op week 3 I've been dealing with this infection. I've been on a round of Keflex and Bactrim and neither have done much for me. My plastic surgeon doesn't seem worried and says it's either a deep suture reaction or fat necrosis. It started with red and irritated areas along the incision and has developed into to this. The incision is mushy and has a serous red drainage. No odor and only occasional sharp pain. Any advice is appreciated.