Ph?

Hey, I think you should flush if possible. I believe it's from too much Nitrogen. Take a look at some pictures on the web and you'll see a lot of similarities.

Without knowing more information on input tds, ec, ph it’s hard to say. But by the look of it this may be nutrient burn and lockout of certain nutrients. If you’re growing in soil shoot for your input ph to be around 6.0-6.5. Check the ec and ph of your runoff as well to make sure nothing funky is going on. If this an autoflower remember that some can be very picky about nutrients and can get by with what is in the soil alone, other autos can be as nutrient hungry as photoperiod strains its all dependent upon the genetics!