Actually, that is more common than we thing
I had a misaligned wafer not too long ago that dug into a little piece of my stoma...I freaked and rushed to see my WOC Nurse...but they said it can happen especially when cutting to fit each wafer. I was informed that it won't go away, but it won't look bad once it heals (just like another wrinkle). Mine doesn't hurt and really isn't bothersome.
If you are still worried, I would see another nurse or even your doctor.
p.s. I hope your rash is better!!