That's weird. I've never gotten shocked from my bike, but I wouldn't say it's impossible. I used to do electrical projects a lot, and I have gotten shocked by some pretty high voltage capacitors, but I have never had noticeable swelling that lasted for a day.

How exactly were you holding you hands? You say your finger was "next to the lever" but that's not very specific. Do you think the spark jumped from the lever itself? Also, what were the weather conditions that day?