Look at it carefully, with magnification if possible. Maybe its something stuck on there? Did you actually drop it or hit it against something? Once a stone is damaged there's not much you can do. To be honest, all of us have jewelry with imperfections. Most of it isn't really noticeable unless we know where and what to look for. I know its distressing, but if you have a little scratch it'll bother you for awhile but it will go away. Just remember to store your jewelry in a soft pouch or box. Don't put a bunch of stuff together, keep everything separate if possible. My best advice would be not to wear your best stuff everyday, and definitely not when you are involved in activity where it could get damaged.