Rash from Chamois?

[Owlie]

Side or back of your thigh? Is it raw?
Try something: put on a clean pair of bike shorts and just do some household work or something. That'll tell you if it's the chamois or the bike.
Personally, I'm willing to say that if it's closer to the back of your thigh, it's chafing from the saddle. I get something similar if the saddle is too "pear-shaped" (ie, the "flare" from the nose to the "sit spot" is too gradual) so that it rubs my leg when I pedal...Especially if the edge of the chamois happens to be right in that area.

If it's closer to the side, it may be irritation from the edges of the chamois. Chamois cream, something like Body Glide or different shorts (are the PI and Terry chamois similar?) might help you there.

Here's some reading for you:
http://forums.teamestrogen.com/showthread.php?t=39475