If it were mine I wouldnt start digging out any material which will only need replacing. I`d get some clear epoxy (even araldite?) and fill indentation.If its on part of board requiring non-slip its quite easy to sprinkle non-slip powder over it.(It will even help disguise repair)
I wouldnt use epoxy putty or anything requiring sanding down.
If you require a smooth finish cover partially set repair with a small piece of clear plastic film;gently smooth over plastic film with a damp cloth; it leaves a gloss finish on epoxy. I
You can use textured / sand paper to give non-slip finish in a similar way to above( rather than powder.. experiment on a piece of wood or something) At first particles stick to the epoxy but they will wear off to leave a textured finish..You can match non-slip with different grades of paper (I`ve found this gives a better non-slip than powder but powder hides more???)
Experiment a bit.
If it aint broke dont mend it !!!