Scratch on MacBook Pro LCD screen (not the glass)
You have no good options for repair. 

Any mechanical stress you add could sabotage the panel later making it more likely to crack. Any coating you try has worse side effects as it ages. 

I would make a judgement call based on the location of the scratch, the depth of the scratch and your temperament. If you can live with it, just continue with the repair. 

If you know it will drive you nuts or is on a part of the screen you look at often, bite the bullet and buy a new LCD panel. Sell the scratched one to someone that isn't as picky (you probably know several people that use a phone with broken glass for months and maybe someone that even uses one with chunks of the digitizer missing). You could probably charge someone your costs for the panel to repair their Mac and come out of it even.