I was prescribed tetracycline for my acne when I was in my late teens as well. It gave me a terrible sore throat (sharp stabbing kind of pain) so I stopped taking it. I've always told doctors since then that I'm allergic to it, because I'd really rather not repeat that.

Perhaps the moral of your story could be: a second opinion can be invaluable.

The moral of the story is that if a medicine makes your kid sick, you get another opinion. This is on the parents.