I use Nu-Hope belts. I'm a little guy, so I mostly wear a 3 inch wide belt. I also have a 4 inch wide belt I occasionally wear. They fit excellent and are comfortable to wear all day. Very good quality.
The belts flatten out my peristomal hernia.
The 4 inch wide belt has a prolapse strap. This strap goes across the bag, flattening my protruding stoma. Works good when I wear tighter shirts.
I don't know if belt use will prevent a peristomal hernia, or shrink it. It might help to stabilize a hernia, preventing it from getting bigger.
Nu-Hope located in Pacomia, California. I order the belts from my medical supplier. They are then shipped to me from Nu-Hope.
Many Ostomymates develop peristomal hernia. The Ostomy itself is a hernia. If the hernia is not causing trouble, and is just unsightly.... it's usually left untreated. Repair surgery has high reoccurance rates. It's hard to fix.
If your stoma changes color from red to gray, you experience constant pain, or have no output for an extended time.... go the the hospital immediately.