I agree light burn at the top of the Plant, but that's the least of your problems. It looks like you have to much Nitrogen, the leaves are too green and a possible Magnesium deficiency, the leaf veins are necrotic. Your trichromes are decapitated. That white trichrome bundle at the top looks wicked. Start at square (1) test soil Ph, soil temp, is the soil wet, is the plant taking up water. Look into Plant Deficiencies Charts. It looks like your not far from harvest, put this grow under your belt. Try and find out whats going wrong so you can avoid it in your next grow. Research the Strains your growing, some Strains are sensitive.
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