It would make me crazy too, to leave it as it is. I agree with others that it looks great, but I would look at the mistake all the time. Maybe you could take a piece of the white and fuse that over the mistake carefully lining up the seam areas and lining the edges up with your quilting, then add berries and holly in the correct spot. Quilting over the "patch" should cover the fact that it's a patch. Being that it is a wall hanging it will not be looked at close, so the repair should not show. Taking out the quilting is a lot of work. The other option I can see is to add holly and berries to all the ornament tops as the mistake is at the top of the quilt. You've really done an awesome job on the quilt. It's beautiful.