I did something similar with this
https://www.halfords.com/motoring/pa...-heater-repair.
I Painted the whole damaged area and scratched the gaps back using a steel rule and a pointy tool (not too sharp). This was much easier than trying to paint the lines neat enough not to bridge tracks.
The results worked perfectly. Though I didn't need to paint the contacts that connect to the motherboard.
I also covered the ribbon with decorators "Frog" tape (what I had to hand, but I suppose any insulation tape would do) just to stop the paint from rubbing off when opening closing the case.