'Slough' forming after mastopexy. Have I caused this? What is the treatment? How long will it take to heal?

I have had a right breast reduction & bilateral mastopexy. My nurse has said I have an area of 'slough'. been told to use betadine 2x daily & use sanitary pads on area to keep it dry. I noticed that 2 other areas are appearing. 2 on the left breast - one on the areola edge & 1 towards the bottom of the scar & one on the right breast toward the bottom of the breast. I'm told they are not infections, but they scare me! The nurse says its ok & will take weeks to heal. I am 3 weeks post surgery.