We're not entirely sure but we'd been fighting through serious undergrowth and crossing barbed for two days so it's more than likely it was cuts, however minor.
Sorry to hear the fume issue. I once had very similar symptoms to yours from inhaling fumes whilst burning off old paint with a blow torch. It's hardly surprising really, after all smoke inhalation has been one of the favorite ways to get a variety of different drugs into one's body for more years than I could shake a large doobie at! These days we use respirators et all when working but seldom when exploring.
Just as an aside I wonder how many peeps get a slightly sore throat and a bit of a bad head after exploring, especially if it's a very damp and rotten building? Loads of peeps I've asked say they do. And that can't be good either!
I think I'll take up crochet...
Thanks again to you all for your kind wishes and comments.