Depends on how much I 'indulge'. It's not really like a hang-over, more like some grogginess in the morning that slowly fades.
And yes, I have had headaches the next morning after getting the munchies and forgetting I don't do well with dark chocolate. "Chocolate contains both caffeine and beta-phenylethylamine, which may trigger headaches in some people" So I don't buy chocolate anymore. Also if not drinking enough fluids before falling asleep is no good.