I would probably get to excited wearing pantyhose and have more problems than a rash.

I have been using a powder called Prantal its fantastic, this has cleared up the rash. Now I wipe a smear of petrolum jelly in the groin before any long walks and wear what we refer to as concreters undies, they are dark blue cotton Y fronts in a larger size than required. So far so good.
We are off on a backpacking trip for a week later in the month there will be a few river crossing etc, so I see how I go.