If it's only a few hours, moist the plants every hour as long as the lights are on. Give them a good soak of just Ph adjusted RO water with Ph around 6.0 for a few day's. They will come back quickly and be fine. Raise the light to promote stretching and that will help to establish new growth quicker. Once they stabilize again you can trim off the dead parts of the leaf. You need to get the internal temperature of the plant down. Donā??t overfeed then with nutrients either. They need moisture more then extra nutrients at this point.