Same thing happened to me, so here's my two cents:
Flushing was the good thing to do if you really had a lockout. To be sure you did it correctly, perform a slurry test of your soil and test the pH and ppm. they should be around the same values as the water you used to flush.
If in fact you had a lockout, flushing the soil removes most of the nutrients in it so you should feed her new nutes soon after but only after the soil has dried a bit, maybe 1-2 days. Don't overfeed her, use the recommended dosage.
Remove the dead leaves so you can track the progress and see if any new ones are appearing. Keep in mind that this kind of problem doesn't disappear overnight, it might take 2-3 days to see recovery signs.
Also I don't know if you know, so I'll just say it. Reading instruments like a pH meter needs to be calibrated from time to time. I personally didn't knew which caused me the same problem.