CGM and barrier question

Hello,
I wear a dexcom sometimes. I began getting a rash from it so i put tegaderm underneath it as a barrier, it works pretty good although i sometimes still get a rash. My question is, can i insert right through the tegaderm into my skin, or will some plastic get in my skin? Or should i cut a whole out for the sensor to go through?

Dexcom says to use only alcohol - anything else could interfere with the coating on the sensor. I’d cut a hole in it :wink: