Usually depends on the tendency of light change (meaning - did you mess it up often/daily basis).. also how long was the duration of irregularity? If you messed it up greatly - did you switch it back or is it still the same as when you messed it up... or is it a completely new cycle altogether?
Every strain will react differently to harsh lighting conditions, but if you've already done the deed... just ride it out and see what happens. Make sure to use the timers, but.... in the future, try to bring a plant back to it's normal routine slowly (an hour a day)...
Hope this helps...