I had a similar experience. They only sent me home with regular wafers, I started experiencing stinging on 3rd day. I took a picture and sent to my doctor as Stanford recommends. I did the powder trick, cut smaller opening and hoped for the best. Fortunately the next day the HH Stoma nurse came, checked everything out and taught me to tear the Eakin ring open and wrap around stoma rather slipping over it. She also suggested Convex wafers. The stoma nurse from Stanford called about the picture, agreed with the convex wafers and called my provider. They, Edgepark, are sending shipper back for unopened packages , crediting me and send me samples of convex wafers pending a new prescription from physician. I had clinic appointment yesterday, taught to use convex and now have that prescription. She also suggested some athletes foot powder to help with the irritation that can occur from the dampness around a poor seal.
It sounds like there's a bit of a disconnect in general care. In my case, I was trained to use the flat wafer. I had stinging a week later. I had an appointment with the WOC at the hospital but it was moved out two weeks and it got quite worse during that time. I went to see the WOC and she put on the Convex. I asked about crusting because it was described here in a reply to me. She did the crusting thing so I learned how to do the Convex and the crusting thing. And the stinging went away after a day or two. The stinging continues for a day or two because of pressure, not because there isn't a seal.
My HH nurses weren't particularly useful. One ordered Colostomy bags for me instead of Illeostomy bags - they didn't know what they were doing. Big difference between care in NH and Boston. McKesson will take back unopened stuff but that would mean a trip to the post office or UPS and it would be easier to give it away at this time.
A little knowledge can save from a lot of pain. Information about this stuff on the web is hard to come by. At this time, it's easier to ask here and wait for an answer.
The training aspect is important too. I have samples of other things which might be better products but I'm a bit timid to use them because I don't have training on them.