Yes, VX is deadly, but no, it's possible to be exposed, wash it off, and be okay. Reality is this is a secret weapon and what little research has been done often does not become public.
Mr Kim had sought medical help at the airport, saying someone had splashed or sprayed him with liquid
Perhaps he didn't act quickly enough. Lesson learned: if an unknown liquid touches you, get it off ASAP.
Unless it's obvious what the best course of action is, trying to detant the attacker and anything in there person would be the most likely source of additional information.
Then you definitely have a chance, but you'll have some interesting symptoms for the rest of your foreshortened life.
https://en.wikipedia.org/wiki/Butyrylcholinesterase#Prophyla...
That said, since Jong-Nam probably got a small dose, that might have saved him, but of course... who'd have had it? Who'd have known? In the military you're trained to recognize the symptoms of nerve agents, because you need to notice the very early ones to have a chance... most people don't get/need that training.
That is not really analogous to having your face in some way sprayed/daubed/covered with it. Your face has large pores, plus your nose, mouth, and eyes are there. I doubt the choice of the face was accidental.
Maybe he could have washed it off, but I doubt it.
Also I agree about the face / nose / mouth / eyes. But the question raised here was about the attacker (not the attacked) being fine after handling the poison.
By the way, one of the attackers was actually not fine: http://www.thestandard.com.hk/breaking-news.php?id=85385