Are you giving your plant calmag?
If not? Do it! It helps with the rusty brown spots.
And give your plant more nutrients overall. It lack of Nitrogen, that’s what makes the plant green. That’s what you need in veg stage. And in flower you need phosphorus and potassium.
Stop giving you e plant calmag when it starts to flower. Level the dosages down don’t quit right at once.
Good luck my friend 😊