Clean dark spot on maple neck

Ddigger

Strat maple neck.  There is a dark spot at the nut end where someones sharp finger nail has dug away the varnish.

How can I clean that spot up and maybe stop it darkening again?

Thanks for your help.

Ddig

Sarge

Wood bleach may work, though I have never used this myself.
I've had moderate success with pure acetone but that was for removing rattle can finish from a screwdriver dent