Let me check on one extra “Skin-Prep trick” with you. I’m not arguing, I just have an idea. 
Unlike IPA cleaning wipes, where you scrub and scrub while the stuff evaporates, the idea behind Skin-Prep is to leave behind as much liquid as possible. Wipe only once, sideways. And if the pad isn’t yielding enough, then use two of them. Use the hisard dryer on the first application, then wipe on a second pad EXTRA gently. You want it to add more solution, rather than dissolve and scrub away the first application.
But Yes: it’s possible that you’re allergic to one of the Skin-Wipe components, as well as the Dex adhesive. Is there any “underneath” plastic film, such as FlexiFix, which causes less IR for you? With Flexifix in particular, cutting a window for the needle insertion is a bit of a hassle, because the layers of “remove this first (paper)” and “remove this from the top side after you’ve stuck it down” (plastic with grid pattern). I recommend an absolutely fresh snap-knife blade for this.
But if there’s any plastic safety film which uses an adhesive which is more “friendly” to your skin, and sticks well, maybe try that underneath the Sensor.