Looks like I rode right by your Campsite near Catavina! Above pic taken in 2002, riding my Vstrom. Couldn't get too far in the sand on that bike! Your bike is better off road! Enjoying your ride report immensely ... keep it up mate ... you've got fans and supporters out here in Cyberspace!
For Montezuma's (which you will get again!) lots of fresh squeezed Orange Juice, Beet juice, Ginger. Eat Papaya. At juice stands, bring your own jug ...
as theirs are rarely washed clean. Avoid Raspberries ... (Hep C). Wash salad makings.
Fresh juices will help bring you out of Montezuma's, will help rebuild your immune system and rehydrate you (important!). Sometimes ... with really bad Turista ... anti-biotics may be called for. I only used them in desperate situations. Sold in any Farmacia. Staying healthy is a challenge on the road. I nearly croaked a few times in my 7 years in and out of Latin America in the 70's. (I ate everything!) Take care!
PS: Just read your last bit about the "inflammation". YIKES! But pretty common. Try to find some high quality baby diaper rash creme. Most are Zinc Oxide.
A good one here in the US is called: A+D. It contains Aloe as well. Great after long days in the saddle, clears up inflammation quickly. A tiny bit goes a long way.