bcipam, the girly bits-swollen-on-one-side happened to me on STP also. My guess was that my saddle was very slightly pointing left and so one side got slammed on the saddle just a little (and after that many miles in one day, a little goes the proverbial long way. It was really swollen on that side for a couple of days, then it was fine). So you might want to check your saddle alignment.