Some of that is the natural thing the plant dose. Your lack of P makes it worse many plants would look like crap but we feed them toward the end of the flower with a bunch of chemistry that they would seldom get in nature and if you have seen weed growing wild they look like hell at the end of flower.
More pictures and not so close to the plant -P in bad cases is compounded by the lack of air movement thru the plant. What are you feeding it? What is the media? did you add a hardener at week 4 or 5?No one here even those who know much more than I are not witches and warlocks they don't use a crystal ball.(I could be wrong about some hehe) They do however work off the pictures and the information you provide. Your nutrient problem if -P as sea mentioned started just after the flip when most lean on the P a bit and is the main ingredient in things like P13/14. The boost in P is what drives the bud size and thickness. If you don't provide it the plant goes and gets it where from the leaves first the fans then the rest.
There isn't much you can do at this stage your close to the flush period and that will make your plant look even worse.
