Hi! I'm answering on my mom's login ;-) I'm a RN who takes care of my mom who has a colostomy. My mother had the same issue in the beginning. She was using a flat wafer with no barrier ring underneath and it was not allowing the wafer to lay flat around her stoma no matter how closely it was cut around the stoma. Stool was leaking underneath and creating redness and skin breakdown. We changed her bag to the the two piece system with a convex wafer. It was easier to cut the opening in the wafer more closely around the stoma since I could visualize it better. In addition to that we used a barrier ring, skin barrier wipes and the stoma powder. And, as someone else commented, I would have it checked out for yeast. This is not medical advice, just the process I use..
I slowly/gently remove the old device, clean the stoma and the surrounding skin with a soft cotton pad and warm tap water. Let it dry. Then I measure the stoma and cut my wafer slightly smaller than the stoma to ensure a close fit, without it being too tight. Put that aside. I take the skin barrier prep pad and go around the entire area that the wafer covers, including the irritated area, getting right up to, but not touching the stoma. Let it dry. I then put a little powder over the area that is irritated only. With a soft cotton ball I spread the powder around over the irritated area until it is barely visable, removing the excess powder if any. I then take the skin prep wipe again and go over the area very gently where I put the powder to seal in the powder creating a layer of barrier and powder, which acts like a thin clear protective layer. I do this two times...skin prep, powder, skin prep, powder and wipe off the excess ( I blow on it to get the excess off ;-)). If you leave excess powder on it might interfere with the adhesion of the barrier ring tape. Then I apply the barrier ring (my mom uses half since it was only leaking on the bottom). I stretch it to the needed shape to fit closely up to the stoma. I then warm up the convex wafer between my hands for a minute before applying it to make it adhere better. After putting that around the stoma, I press it down gently around the stoma/over the barrier ring to create a good seal. I move my fingers around the area around the stoma with light pressure for about 1 minute. Then put the bag on the wafer. I use the lubricating gel (forgot the name) inside the bag so the stool slides down to the bottom of the bag more easily and does not hang around the stoma. If my mom has stool buildup around the stoma at any point, I remove the bag only and gently clean the area around the stoma so it has less of a change to go underneath the wafer, then click the bag back on. This is tricky because when wiping you don't want to push the stool under the wafer, so use your better judgement if you do this. I know this is a lot of information. However, I would have loved to have this information when we were trying to figure this all out. I am a Neuroscience RN, so this GI stuff is somewhat foreign to me! lol! This has helped my mom's skin tremendiously and she no longer has any skin irritation. I think the skin barrier, powder, convex wafer and barrier ring might solve your problem. Thanks for listening. Good Luck. Hope this helps ;-)