The rust spots on the leaves are getting worse. I ...

if you flushed and it got worse it means it is not a nue burn. it looks to me like a big nute def. the fisrt 2 pics looks like a heavy potassium deficiency, the third a lack of phosphorus and in all of them i see nitrogen def. in my experience under qbs, like yours mars ts, plants need more k than under hps or cobs. to solve this i would feed her with some bloom fert (like n.p.k. 2.2.4) and a strong pk (like 13/14). but go easy with them the first time and rise a bit every time.