There's lots of way to fix it, but no way to fix it will be completely invisible. Even a re-cast is not fool proof because you get the slightest bit of dirt or air trapped in the damaged area and you can see it. I would contact the person you purchased the blank from and see if there is anything the two of you can work out between you. Certainly doesn't sound like the creator is at fault and certainly he is not obligated to fix or replace it, but you catch him on a good day even if you were the culprit that broke it, and you never know what kind of deal might be worked out. Never hurts to inquire.