You could try filling the dent with water as suggested and putting the tip of a soldering iron in the water. But you have to be really careful. It's tricky. If you fill it with something clear like a varnish then you will still be able to see the dent, it will just be a flat surface. The prominent grain makes it really tricky to fill, but you could try matching a shellac stick and filling it flush with that? Other than that then it is either a patch time, or routing off the top and replacing it unless you can live with the error.