My husband's stoma was also flush to his skin and we had a lot of leaking problems at first. Even when we got his leaking under control, he could only keep his bag on for 2-3 days before changing it. He also preferred not to wait. We also had to switch to convex pretty quickly... he also wore a belt while he had the stoma. This helped pull it in more.
We also switched from eakin seals to using paste. He found the paste created a better seal and stuck better. He also would layer the powder with barrier wipes. So, he would put powder just around the outside edges of his stoma and then wipe the barrier wipe over it. Eventually, the skin crusted up. Also, we realized we were cutting the wafer hole too large (as his stoma shrank over time from the surgery), so we reduced the size of that as well.
I bought him these baby wipes called "Water Wipes". They are purely made out of water and didn't interfere with his wafers sticking.
Hope that helps a little!
Post Edited (Amythyst) : 5/20/2013 4:11:56 PM (GMT-6)