To answer some of the questions above:
These were indeed the vented plugs, but I did not actually check to make sure the vents were open, and as I have thrown them away, it's too late to check now. I do not typically have a lot of wax built-up, so I don't think that was the problem, but I cannot completely rule it out.
I concluded that I had not punctured the eardrum because my hearing is not affected. Once my ears dried out, I listened to my iPod, alternately removing one earbud and then the other, and could not detect a difference. But I will take the advice above and visit the doctor once I get over the head cold I picked up on the way home (17 exhausting hours of travel in one day).
Clearly, they are not for me, and from now on I will just endure the uncomfortable feeling of water in my ears after diving. And considering that some of you report using them without problems, I will downgrade my warning from "Don't ever use them" to "Be aware they can cause serious problems."
I've never been allergic to anything, so I doubt an allergy was the issue.
Of course, it is always possible that the problem was unrelated to the earplugs, but I was not doing anything different on that dive, except using them. I also cannot be sure that they were the right size, but I did use the sizing kit before ordering them. And I cannot be sure I had them in properly, but they felt good before I entered the water.