Give it a little more time to see if it's just dead top growth or if the stolons/roots have also been killed.
A couple weeks ago, someone working on my fence left a couple concrete pavers sitting on my St. Aug lawn. I noticed them after they'd been baking in the sun for a few hours. The grass underneath was wilted and by the next day looked crispy dead. But it all grew back within a couple weeks because it was just the grass shoots that fried. The pavers weren't there long enough to kill the stolons/roots.
But I've also experienced what's happened to your lawn. Last summer (before I cared about my lawn at all) I forgot to turn my irrigation system back on after a week+ of non-stop rain. Then we had a week+ of 90 degrees and no rain whatsoever. I lost a lot of grass that never recovered and I had to lay down new sod.
Unless you start seeing some vigorous uniform re-growth, your grass is probably dead.
The fix is simple. Make sure your irrigation system is putting down enough water everywhere. Had that grass been irrigated properly, it wouldn't have died.