Had the same issue with mine, accidentally measured out the wrong nute when feeding. I did a flush with 4 gallons and ff sledgehammer, and all is good now. Noticed recovery within a few days. Good luck.
What did you end up doing with those side branches? Im in the same boat, getting ready to flip to flower, but dont know if i should trim the lowest side shoots growing next to the main colas. One of my White Widows is growing great with minimal side branching, but the others not so much.