Do you need to touch up scratches on carbon frames?

I know this has been asked on other topics before but I struggled to find a definitive answer.

I have managed to scratch the paint on the bottom bracket of my carbon frame due to a misaligned front mech throwing the chain a couple of times.

I say scratch rather than chip as it is very minor. A friend told me I need to cover it in some lacquer or nail polish to protect the carbon, however it’s so minor i think touching it up will make it look worse than better.

So in short, do I need to touch it up or can I leave it?

Thanks for your help!