Congrats on the new Dexcom! You’ll love it so much. Don’t be scared by the insertion device—it seems big/bulky/scary, but the actual wire that stays in your skin is a bit longer but MUCH smaller than an insulin pump cannula. It’s totally painless! But I will say that I sometimes have problems with my skin bleeding if I try to do the insertion slowly—so I’d suggest pulling the clip off and pushing down on the plunger very quickly to just get it over with.
As far as where to put it on your body, my favorite places are my stomach, backs of my arms, upper thighs, and love handles. Pro tip about using it on your arms: This is the only place you’ll probably place the sensor vertically instead of horizontally. Make sure the “G5” (not the “Dexcom”) end of the sensor ends up nearest your head. So, insert with the plunger going upward into your skin instead of downward. I’ve found that when I have done it downward in the past, the weight of the sensor pushes down on the wire going into my skin and causes that area to start hurting and aching around day 3.
As for how long to wear it, I know there are lots of people who wear it more than a week at a time, but I am always hesitant to wear it longer than you’re supposed to (that goes for both my CGM and my pump) because I find that my skin heals better if I wear my devices for shorter periods of time. I don’t want to end up all scarred. I wear mine for 7 days and no longer. Sometimes, depending on where you’ve placed it on your body, the adhesive will start coming off. You may want to purchase some GrifGrips (or something similar) that have the Dexcom hole cut out in the middle. Another pro tip: Don’t put on the GrifGrips when you first put on your Dexcom. Wait for your Dexcom adhesive to actually start peeling off your skin first and then apply the GrifGrips! For me, if it’s going to peel, it’s usually around day 3. If I use GripGrips too early, they can start to peel by day 7 as well. There’s probably a better brand out there that has the same products of GrifGrips but doesn’t peel after a few days but I just happen to have bought the GrifGrips brand haha.
Good luck with starting your CGM!!! Oh, and be sure to set your loved ones up with the Dexcom Share app!
Oh ps—almost forgot another piece of advice that I just learned recently… when you change your sensor and start a new one, that’s when your new sensor will be the most off-base from your actual blood sugar levels. I read on a few T1D Instagram posts about a process people have termed “cooking” your sensor to make it more accurate when you first switch sensors, and it actually works! Instead of taking your current sensor off and placing a new sensor, place your new sensor site 4-5 hours before you plan on taking off your old one and switching over. This lets the new sensor wire “cook” (not sure why this term was chosen haha) and get used to your body before being activated with the actual sensor. I’ve found that, although weird, this actually really helps my sensor get calibrated a lot more quickly!