I've used cavilon skin barrier wipes and they don't effect wear time adversley. They provide just enough of a film to protect the skin and allow it time to heal and the bag still sticks on ok.
Also sounds like your stoma could be convex, they do special bags and adaptors to push the stoma back out so it stops the leaking under the wafer bit.
Have a word with your stoma nurse as they should be able to give you samples to try and find which one works best. Stomas do shrink and change a few weeks after surgery so best to keep a supply of different types of bags until swelling from op all settled down.
Crohn's dx 1989, loop ileo 1992, end ileo 1992. Arthritis developed 1990 Stoma abcess 1995. Azathioprine started 1995. Panprocolorectomy 1999. Stillbirth 2000, antiphospholipid syndrome dx 2000. Flare up 2004, stoma abcess and strictoplasty 2004. Low blood pressure dx with impaired kidney function 2006, fludrocortisone pres. flare up 2010, steroids, Humira, codeine.