In 1983 I had all four removed at once. The Navy "dentist" told me to bring my walkman along, so I did and listened to Rush - Moving Pictures. I actually fell asleep with just a local. Afterwards, he said keep your mouth shut for 24 hours. No smoking, no eating, no straws, just sips of water. By the same time the next day, the swelling was gone and I wasn't bleeding. Just exploring these huge caverns in my mouth.
The rest of the story:
At the same time I was having mine done, a neighbor of mine was having his done. Due to the impacted nature, they put him under with an IV. The IV "nurse" blew it a couple of times and the site became infected. a few weeks later gangrene set in, a week after that, his arm was amputated at the elbow. I haven't been to a dentist since. Irrational but still afraid.