I would first try the wetting it and attempting to block it. Then look hard at the size issue. I also believe it is a combination of sewing in one direction and bias edges. If it is still off kilter enough to bother you (more than a border would correct) than you may need to add sashing. Depending on the correction needed and how many braids you have, you might be able to sash every in strips of 2 or 3. Example - you have 7 braids and you need to correct 1" - you could sash between braids 2 &3, between braids 5 & 6 and the 2 borders. Each of these strips would only have to be 1/4" different from top edge to bottom edge. If these sashes and borders would only need to be off by 1/4" at one end, this would not be noticeable. But, sew in the opposite direction than you used to sew the braids together. Both of these would be a lot easier than taking it all apart!