What Causes Low Grade Fever And Body Aches After Mastectomy?

I am a 52 year old woman. Had a mastectomy for dcis on Feb 4th with reconstruction/expander placement. I had a drain in place for 4 weeks. Started having a low grade fever, body aches, headache 5 days ago. Went to my plastic surgeon in case it was an expander infection. He believes it is because of my symptoms and my breast is swollen and sore. I was placed on Augmentin 875mg twice a day, and told to call him back if I see no improvement in a couple of days. My question is: does oral Augmentin have a chance to get this infection under control?