Watched a really convincing documentary the other day (yes I'm that sad, Arillas forum or documentaries...) but they put two subjects in a room full of mosquitos, and one didn't get bitten at all (like Daryl and me) and the other was mullered (like you were.) The immune ones naturally produce certain chemicals (called ketones) and the mozzies just run away. Sadly Mythos is not the answer....
DEET is a ketone, if a bit complcated. Look at wikipedia if you want to know more. You need at least 50% in what you use. Jen was destroyed by Arillas mozzies in 2003. We stayed away for 4 years. The scars on her legs are still visible.
This July she got one bite - at the airport on our way in after she had washed (the DEET off) her hands. But she covers up when they are at their worst - early evening. Like Airrea and Heavy, she didn't get one more.
Hope this helps
Phil