Re-vegging a poisoned plant 4 weeks into flower?

I had a friend of mine look after my girls for a few days while I was out of town. I dont know how but somehow he managed to fuck one of them up royally. It looks to be like she was hit with way too much phosphorus and as a result, all of the hairs yellowed and 80% of the leaves died. Im in week 4 of flowering and im going to try to re-Veg her in an attempt to get some foliar support back. Then ill try flowering again.

Is this just wishful thinking or can this be done without harm to the plant or without herming out?

Only one fucked up, Did he do something diff. with that one or is it a retard plant sometimes that happens, POST PICS REALLY HELPS>

im revegging now. Pics to come soon. It was a smaller plant and i think he fed them before they were ready. Im using big bud so two close helpings on a smaller plant is probably what overloaded it.