Correcting printed PCB (add a via)
I suggest you combine the two methods. Drill a hole near the traces and thread a thin bare wire through the board, lay it along the exposed traces by a few mm and solder it on both sides. 

If you don't have such a wire handy, just strip a piece of stranded wire and use one of the strands

Nobody will notice unless they look very carefully, and it will be reliable.