I recently had emergency surgery due to a perforated bowel and abscess from diverticulitis and have been dealing with similar issues to what you've mentioned. I had a severe allergic reaction to the adhesive on Coloplast bags (the ones meant for sensitive skin, as well as other Coloplast products). One of the worst parts was that the ostomy nurse in the hospital kept telling me I just needed to get used to the bag. Well, I ended up not being able to keep a bag on and ended up back in the hospital for another 5 days as a result.
I have found Hollister bags have been tolerable and are not having the same reaction on my skin (which was burning and itchy), which has helped; however, I am still having reactions to a lot of adhesives, so I don't put anything near the skin on my stoma without first testing it on the other side of my abdomen.
Unfortunately, with the skin that angry, there isn't just one easy solution (at least there wasn't one for me) - first, I need to stop putting things on it that are irritating it and second, find a way to keep a bag on while also getting the skin to heal.
Also, my stoma is significantly retracted, so leaking is almost guaranteed… we are hoping every day that it just keeps on working and doesn't pull in further, as the doctors do not want to go back in anytime soon due to the significant risks that would pose.
Anyway, I am still having issues, but currently, I clean the stoma/area with just warm water, will use Domeboro on it, then wash it off if it's irritated. Once dry, I put stoma powder wherever it's red/irritated (don't cake it), then do skin barrier spray to crust the powder. Then I lay back and pull the skin up to do the rest so the stoma skin is more of a circle and there are no folds. I then use hydrocolloid strips all around the outside skin of the stoma (because I'm having leakage problems and the significant retraction), then use the Adapt paste along the bottom edge of the stoma (doesn't seem to be bothering me - Convatec paste I reacted to and cannot use), then holding the skin up, I put the convex Hollister bag on (it has 2 different ways of adhering to the skin - directly around the stoma, then you rip off other pieces for the part that adheres to the outer skin - this provides for better adherence), then while holding the skin up, I press on the bag/adhesives with my hand or heat pack for 5-15 minutes. Then I put the belt on.
This has not been perfect, but it has been the latest experiment to keep the bag on at least 2-3 days without leaking and to get my skin to heal, and my skin is significantly improved.
I know this was super long, but hopefully, it helps you in some way. Take or leave what you will, but your picture looks like mine did, and it was an allergy to the adhesive, which at first, nobody believed, so I wanted to share. Hoping something in my experience helps you, as it's been a really rough 5 weeks and counting for me, and I don't wish these issues on anyone.