Heat hasn't upset my barrier too much, but when I get itchy under the tape part of it, I squirt a tiny bit of nasacort on my fingers, wipe it around the itchy area, and continue with my normal barrier application. I usually do this maybe twice a month. I picked up this tip on another ostomy site, and it works great for me. I checked 1st with my dermatologist who said it wasn't a fungal or yeast thing. Maybe your son could run this idea by his ostomy nurse or dermatologist?