does your pot drain? it could be lockout from lack of drainage. Those ferts need to breath. It may be benificial to drill a dozen holes around the bottom of the pot your working with for a little added airflow. If your worried flush with Ph'ed water, don't add nutrients after, maybe a little bit of blackstrap molasses for bacterial benefit, and let her get back to health, before you start with more nutrients (1-2 weeks) Weed can handle growing and repairing without huge amounts of nutrients.
Also when you add nutrients you water right after correct? When I first started growing I made the mistake of adding nutrients and then not watering with fresh water right after, over the course of a month or so the build up of nutes on the top of my plants started to kill them, because the roots had filled out and started to get to the surface which was saturated with salts and other things.
Also you can replant it. It is not all that bad at this stage of growth to pop the little rootball out and repot it in something else.
Just a thought, if you think the problem is nute burn, why don't you treat for nute burn and see if it gets better.