I wouldn't worry, it will be ok.
No need to flush or do anything drastic, in a few days it will be growing in leaps and bounds and completely unaffected by what has occurred so far.
The twisted leaf is not associated with the soil conditions, just a common growth in cannabis leaves.
Remember too, no plant will ever have 100% perfect leaves, 100% of the time.
So, no need to stress, everything will be fine.
Cheers, Organoman.