I concur with everyone else, this hive should be requeened. This will change the genetics of the workers so that as the older mean bees die off, they are replaced with nice bees from the new queen. Michael's instructions are what I would follow if I were you, provided you have the equipment necessary.
I also agree with Jim that those thick leather gloves tend to make bees irritated, and I usually wear two pairs of nitrile gloves instead. I hardly ever use my leather gloves, and never when I'm doing an inspection, regardless of how angry the colony is. Also be careful when you are removing and replacing the upper box that you aren't crushing a ton of bees underneath it when you set it down.
Also be sure to wash your suit before going into them again, as the suit is now full of stingers and smells like alarm pheromone.
Jim's smoking technique is very effective. Smoke the hive entrance and/or under the screened bottom board heavily, wait 10 minutes, smoke them again, wait 30 seconds, and then open the lid.
Don't worry about localized swelling around a sting site, even if that swelling is severe. This is not a sign of an allergic reaction, and especially with multiple stings, it's completely normal. I have been keeping bees for 5 years, and I swell up like crazy almost every time I get stung. Provided you aren't allergic, which most people aren't, you'd have to be stung over 1000 times to be dosed with enough venom to kill you. I know it's unpleasant, but even if you get stung a bunch of times, you should be okay.
Whatever manipulations you need to do to requeen them, try to be deliberate and intentional about all your movements. Don't flail, swat, or move haphazardly or aggressively. Don't be slow, but be purposeful and careful to try and keep them as calm as possible. Keep us posted, and hopefully it all goes well.
