I've also heard that the more you get stung by bees, the more allergic you become. It's not like other things where you build up tolerance to it, you get more allergic. So if you get stung a lot, your symptoms will get worse.
Thats what has happened to me, when I was younger and got stung, nothing much happened, just mainly hurt for a while. Now I swell up pretty good.
My dad is really allergic to bees, he got stung one time and swelled up good and passed out, had to rush him to the ER to get a shot.