While I appreciate what Bill is saying it comes down to how it got scuffed in the first place. A model that noses over at idle and lower ground speeds and gently brushes the tip a number of times and gets a bit worn as a result can easily be saved. But a single strike that causes this level of damage is often reason to get a new prop. In particular if the engine was running above idle.

One thing I've noticed about APC's over the years is that as they suffer from impact or wear they generate whitish spider webb'y areas or single white'ish lines that can be seen in the grey surface. If you see any signs of that then it's time to retire it to paint stirring. I would check carefully around the tips for any signs of these white marks.

And with ANY APC I always make it a point to check the hub and blade roots at the beginning of the day. I've had multi year old props develop these white marks in normal use as well but it does take a few years.

And if this was a wood prop then I would suggest a new one immediatley. Wood props tend to develop splits along the grain and sudden stops are a prime way of doing just that, even at idle.

I ran a glow type 10x6 on a gear drive electric model that belly landed all the time. I would try to level the prop but it was not always successful. After a season the blades were very spider webbed from catching and bending but since it was operating at such a lower RPM (~5000) it didn't worry me but I DID make it a point to test it by test flexing it a bit now and then just in case.

So use a little judgement but if in doubt then I would get a new prop. An 18x6 is not an engine and prop combo to be trifled with.