You're Nitrogen deficient but also show fert burn.
Flush VERY well with water at pH 6.8.
Feed immediately with a VEG fert which will have a higher first number, or a bloom fert with some added fish emulsion (less than the bottle says, as even bloom ferts still have some N in them). Your plant is very hungry for N, but you only want to give this one feeding with N since you are in flower. Then go back to your regular bloom fert.
You will also want to re-pot into a larger pot. Yes, it's safe in flower; in fact, I like to re-pot during week 3 if I am doing a correct potting schedule.