Is a crusty and yellow discharge normal?

At 7 weeks the wounds should have healed. Occasionally you can have some issues with dissolving stitches around the areola. If you are having nipple discharge you need to be seen and assessed.

This is obviously a question you would have to ask your surgeon. He knows exactly what was done at the time of surgery. It sounds more like a wound discharge than infection but it is important that at this time you ask your surgeon as to what is going on.