This venerable old girl suffered a cracked heel at some stage in the distant past. As you can see, the repair wasn't the least invasive solution that could have been imagined at the time.
These big-ass screws have kept it (sort of) together but the instrument deserves better. I'm not going into detail on the heel repair here—take my word that it's all glued up and sound. Instead I want to look at how we can minimise the damage those screws have caused.
With the screws removed, things don't look too pretty, do they? Incidentally, the two small holes in the fret slot are mine—I drilled them when trying to steam out the neck to repair the heel and they'll be plugged and covered by a fret. The medium hole is a loose pearl inlay dot that'll be replaced later.
The holes we're worried about are those big, jagged ones.
Of course, we could squidge a pile of coloured filler into them and smooth off the top but that's not going to be the nicest looking repair. We could cut some plugs and glue them into the hole. If we get a reasonable grain match, that'd be a better option but still not the neatest.
What we're going to do is to replace the entire section of fingerboard between these two fret slots. Effectively, we're going to remove the rectangular section with the damage and *inlay* new wood.
A bit of digging around my rosewood stock (and scrap pile) turns up a piece with a similar colour and a pretty close grain match.
If you look closely in the photo, you can see that I've actually routed out the damaged part but left a tiny sliver along the sides of each side. That sliver will keep a nice contiguous look along the edge of the fingerboard and save messing about trying to match the aged lacquer.
As luck would have it, this instrument needed a refret too. It'd be much more difficult to accomplish this well without refretting.
You can see the new fingerboard wood in the photo below. It's a good match for colour and grain and, once it's all clean and oiled, it looks pretty damn good. Stung up, you'd be pretty hard-pressed to notice anything.
Much better than filler.