In reply to cb294:
Eeek! Sounds traumatic. I used some sudocream when I got back which is antiseptic, and that seems to have helped a lot, feeling fine today, but will keep your experience in mind!
I did actually have some wet wipes with me so did have a quick wipe around down there the night before, but I'll take more with me this weekend. Getting into your sleeping bag covered in dried mud on your legs and arms and salt from dried sweat everywhere else is kinda gross feeling so I try to do some basic personal hygiene with them anyway, but will make sure I have more next weekend.
I might also swap the saddle from mountain bike for the saddle on my CX/commuter/do-everthing bike, as I know for definite I can use that saddle for multiple days with no problems.