Sorry to hear man, ya flushing was the best idea, then you should have added nutes at say 1/4 strength IMO, but only if you flushed properly with 3 times the size of your pot..
Hope it recovers, just keep at it, dont toss it, I had a few like this, and they still lived and produced good bud.
...I was just thinking, I had a stunted plant like this, and it was because the soil had slow/time release nutes in it... So if this is the case, I would not add more nutes, but if not, then yes add nutes at a very low strength after flush.
:smokebuds: