Tonsilitis is just so much fun. I can't recall how many times I had a round with it when I was a child. Even as an adult, I still have a set of rather ugly tonsils that usually startle doctors who have not seen me before (chuckle). I rarely have a sore throat these days, though, unless my sinuses are acting up.
The swab they do now, by the way, is to check for strep. It only takes about seven minutes now, but years ago, it took a full 24 hours to see if the culture produced any strep bacteria. A white blood count check will also answer the question of whether the infection is bacterial in nature, and whether antibiotics would be the appropriate treatment.