There can be many causes for what you're describing, so it's important to figure out what's causing it before you start throwing solutions at it. In some cases, depending on the cause, using certain things can make it worse. Contacting an ostomy nurse would be the first thing on my list to do. It's easy to email them pictures of what's going on and get their opinion. In case that's not an option for you, here's a link to a good article that briefly describes the most common causes for what you're seeing. The second link is for a great picture book on stoma and surrounding skin problems and how to deal with them. With those two things you should be able to narrow down the cause, and quickly get it under control.
Let us know how you are making out!