I took 2g of tylenol at once for severe pain. i became very nauseous & violently threw up 6 hrs later. 3 days later, im 100%. did i damage my liver?

Not likely: While a high dose to be taken at once, max dose per day as recommended by manufacturers is 4 g. It appears more likely that the condition causing you the pain in the first place might have caused the vomiting episode eventually. Pain itself, if uncontrolled can cause nausea and vomiting. If any reason to believe that there might be liver damage have your liver enzymes checked.