Bring Plant Back

My Plants Leaves Shrivelled Up After I Turned It To 12/12 Ligtht. Can I Save It? WHAT DO I DO? SHOULD I JUST START OVER?

The long answer will be yes, with an if.
The short answer remains no, with a but...

did they all shrivel or just some? Are they brown, spotty and crunchy or are they green and squishy, but just curled? Do you have pics? Is there more than a 15°F temp difference during the "night" hours? Are you growing in soil? Are you using nutrients and if so, what kind and more importantly, how much? How soon did they shriv after the cycle changed and what have you been doing differently since the cycle switched?

Can The Temp Do This? And What Should I Do