I've cured myself of the symptoms of the bites, but it happened in an unexpected way.

There was something really wrong with my rear leg, and my whole body was starting to go weird on me. I was feeling kind of nervous in general, like how you feel when you drink too much caffeine (or I presume, if your name is Pinkie Pie). I put together a harness with couple of refracting mirrors and a microscope to look at the bite up close. Applejack was wrong. These are definitely puncture wounds. They're very faint, but still visible, and about six centimeters apart, with a recession of around two millimeters. The striations on the epidermis clearly indicate a puncture rather than a tear. It wasn't mosquitoes. It might have been a bat or something, except the punctures are much too widely-spaced.

I thought about going to Ponyville Hospital to be extra safe, but I really don't want ponies to think of me as a prissy princess, and I know it it's not rabies or something horrible because the surrounding nerve tissue tests functional. I couldn't get the nagging sensation out of my mind, though, so I looked around for a spell that might do the trick. I found one scrawled in the margin of an old book (the same one Spike found behind the bookcase last year) which is supposed to neutralize the effect of magical bites. I didn't expect much, but figured it was worth a try (and I can't pass up the opportunity to learn a new spell, I mean, c'mon).

It was a hard spell to cast, but to my surprise, it worked! My leg aches just a tiny bit, but the tingling and jitters are completely gone. I think I'll do some field research down at the orchard to find out what caused this. Was the creature that bit me magical?