It could be a suture trying to work it's way out or one of the sternal wires may be causing an irritation. I would definetly stay on top of it though...you don't want that infection to become a real problem. I developed an infection several weeks out and my cardio slapped me in the hospital so fast I didn't have time to even realize what was going on. You may need to get an Infectious Disease Dr. on board to get it cleared up.
#1 OHS 1980 Wolfe Parkinson White, Duke, Dr Sealy.
#2 4/08 Tricuspid Replacement (31mm St. Judes Biocor), ASD closure with Bovine Patch, modified right sided Maze Procedure, Mayo clinic