My trick is to just continually wipe it off with a burp cloth. It's a pain in the butt for sure but the rash would be painful/uncomfortable, I'm sure, so I just deal with it. She did start getting some irritated skin one day so I put a little Lansinoh on it every time it got worn off and it seemed to help (although she didn't like the sticky texture of it...hah).
My lo has sensitive skin and usually gets a little rashy on her cheeks everytime she tries a new food. She also used to get a rash from her paci if she had it in for even a few minutes. I used to put a little emu oil on the red areas which helps with redness and inflammation.