https://www.jaycar.com.au/circuit-board-lacquer-spray-can/p/NA1002
You can use this to cover the tracks. It looks like it needs a bit more sanding with a very fine grit to get as much shine back in the copper as possible. If you sand through a track you can put a jumper in.
+1
Use Isophrophyl alcohol to clean the area after your work is done - before using the lacquer.
