Dexcom and tough pads

Ok so one of my really awesome friends gave me a tough pad to try on my arm for my Dexcom. It was working great but now it is falling off on day 4. I cannot use skin tac wipes to help adhesion (allergic) but was a loyal opsite flexifix user for 3 years but wanted to give these tough pads a try since the opsite tape make me too self conscious when wearing it on my arm with short or no sleeve shirts. Are there any tips to keeping the tough pad on for those of you who use them without any additional products? One edge is peeling up and I can see under it, my arm hair is all that is keeping that side stuck on. It also failed this morning but I restarted it and its working good, but falling off. Its expired so Dexcom will not replace it, I didnt even bother calling to ask. I am guessing that this product just doesnt work with my skin type and I just have to go back to opsite 100% of the time. The sensor itself will not stay on me at all so maybe next I will try opsite flexifix down on my skin first and then the dexcom sensor and see if it will stay on that way. I have yet to try that method.