Plants will store it though and the medium isn't the only thing which you have to sort out once a plant is over fed. It's like you eating too much... take the food away and you've still got what's left in your stomach.
The plant needs to metabolise that excess and when it is burned like that, which can take weeks, especially if it's been flushed and had other things done to it. It's why I don't recommend putting epsoms in. Really they can cause more harm than they'll fix, especially in a medium which is already probably out of whack.If you want to give them you should foliar feed them, but at this stage in flower that;s not really a good idea either.
Treating plants and getting it right is hard for this reason. People sometimes expect results within hours or days, like they'd see in us. Plant physiology is obviously a lot different and you might take a week to see even the first signs of improvement, if at all. In a var which takes 8-9 weeks to complete it's cycle, seeing problems like this at week 5 means you're not going to have a perfect plant come the end, that's just the blunt truth of it.Nothing will "fix" this now. Main thing is to make sure it doesn't get worse.
Take care