Repair. If there’s something you did wrong, just go there and fix it. If there is something to be announced about that, do a small announcement after you fixed it, express your true feelings about that, and let it go. Don’t try to excuse yourself without repairing, just to polish your public image. Every PR company will rush you to “go out” with a nice press release in which you acknowledge and excuse, but that will also empower the negative opinion, not you.
If there is something wrong with you and that negative opinion is about that, you should be thankful. Not everything that feels like a slap in the face is something wrong, sometime you deserve it. It’s like a road sign that tells you: closed road ahead, just turn around. Those negative signs are things you should be grateful for.