Honestly, of my 9 leopards I kept and adjusted to captivity (one died and two I sold) 4 of them hid for 2-3 weeks, 1 for nearly a month.
Do not dig for her, it will reduce your odds of success.
I also noticed that when they decide to finally emerge some just jump out like nothing ever happened while others take several days to venture out completely for more than a few minutes. They'll stick their heads out, often around feeding time and look around safely in the sand. Don't scare them this is good news. It's also hard to spot them (and that's intentional) doing this. Walk slowly by the tank and especially very early in the morning (perhaps before the lights come on) and late just before and after the lights go out, look for it swimming around or peeking out. They're on a very different schedule than we are and it can take a month or more to transition.
I had a black leopard wrasse that for more than a month was only out for maybe 30 minutes of tank lights and seemed to night hunt, because I caught her swimming around long before the lights turned on in nearly black conditions. I was surprised they would do this.