Hangover =/= alcohol poisoning. Alcohol poisoning is while you are under the influence, hangover is when you are not drunk anymore.
Hangover damage reduction: Drink water, lots of water, before you go to bed. Eat something high in salt and/or sugar. Drink more water. You probably won't piss yourself, in fact, you probably won't even need a piss when you wake up.
An asprin before bed and first thing in the morning can also help.
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Leik, OMG