It enters your body through your eyes mouth nose anus penis and skin then you start violently coughing then your lungs stop working due to your muscles not being innervated correctly than you asphyxiate pretty painfully under convulsions. You need to get between 86 μg to 10 mg by intake over the skin to die but other effects are like losing your eyesight or a running nose which can be also permanent and need way less of a dose and it takes about 5-10 hours after dermal contact for the first symptoms

It turns off your muscles' ability to relax and then you flex to death. Normally because you're no longer breathing.

https://en.wikipedia.org/wiki/VX_(nerve_agent)
Is an oily amber substance not a green gas. Afaik gives you a painful spasm followed from the inability to operate any muscle diaphragm included so you get contracted then flacid and die from asfixia. If you happen to survive the sarcospasm you probably wouldn't get well anyway since the agent messes the nerve receptors forever. It can be absorbed by skin contact and the lethal dose is so low that some symptoms depicted in the wiki are more "supposed" or "by account" rather than a fact fun fact some teorize it would have been what Bruce Willis puts in his car in the movie the Jackal and kills the guy that touches it after. It acts in minutes and survival rate is almost non existent without the antidote...