Diaper Rash? Please help!!??

My son has been having what I can only describe as wet farts. Every time I change his diaper, there's a little bit of poop on his butt and diaper. But not enough to actually say he pooped. It's giving him an awful butt rash. It's raw, and looks like it's skinned between his cheeks. He doesn't like it touched and gets fussy when I clean him up or touch it to put the creams on him. The nurses have tried triple paste, and Desitin. They're gonna try putting oxygen on his butt but obviously I can't do that at home. Any suggestions on what I can do when he comes home to help? I know no diaper is an option. Any tips how to do that without a mess? I'm really needing some advice on this.