Hi there, skin looks very irritated :( I had an itchy, red rash from the beginning of time and have to take very good care of my skin for over 20 years. I am fine as long as I am diligent on every single appliance change!
Never use any products that contain alcohol!!! Wash skin gently with luke warm water (no soap) and a soft cotton round (cotton ball). Use ConvaTec-Niltac to remove any stubborn leftover adhesive if necessary.
To get the rash under control initially, see a doctor or dermotogist to get a prescription for a topical steroid cream. Apply very small thin layer and let dry well (5 minutes) before applying anything else on top. Wrap the stoma with bit of tissue to keep skin dry while you wait. Long term use of steroids thins the skin. I eventually replaced the steroid cream with a safer cream called Elidel 1% (Pimecrolimus). I use it every time I change appliance for years now. It's important to put clothes on right away for the pressure to help the appliance adhere to the skin.
Until the rash is under control, apply Eakin Cohesive skin barrier after applying steroid cream. Then apply the flange etc...
Once the rash is mostly improved and you are no longer using Easkin skin barriers, continue with prescription Elidel cream, then apply alcohol free 3M Cavilon no sting barrier film, alcohol free Colopast Brava Strip Paste, Coloplast Easiflex Flange and Pouch.
Never change 2 days in a row as it is hard on the skin. I go 6 days between changes. If I get a small irritated spot, I will use zinc cream (diaper rash product) just on that little area. I find that heat, direct sun and too much sugar in my diet causes candida and flares the skin.
I sure hope something listed above helps you. I've been where you are and it is very painful and concerning. I no longer have this problem thanks to Elidel cream and alcohol free products. Good luck :)