damnit

Im 4 weeks into flowering and I just broke the top 3-4 inches!!! How bad could this be???

nothing you can do now-was it a clean break or a bend/snap

as clean as it gets

6 weeks in- I think you should be ok-just keep her as least stressed as possible. at least all the lower nugs will fatten with the extra light. if indica, you should be able to smoke that top cola after drying and curing. did u check the trichs on it?
it happens to the best of us.