I think my baby's gonna die

Okay I got my pic situation straightened out. Here's some pics from yesterday

So I thought this little girl had pulled through but she seems to have relapsed. After I figured out she was suffering from nute burn I switched her from Fox Farm's ocean forrest to a 50/50 mix of ocean forrest and light warrior. She still looks weak and very unhealthy. Should I feed her some grow big? I'm afraid of the nitrogen content, but I don't know what to think any more. I've been adding super thrive to try to feed some vitamans. My other 2 plants are still very healthy very happy. Please someone help me save this little girl.

A little help please.