I noticed the exact same with myself just as Jasi mentioned it unfortunately

Not a rash exactly…but I do notice when I have abdominal pain or my period is starting and usually only when I’m getting out of the shower, certain spots turn bright red on my abdomen. My PT told me years ago that it tends to happen in a lot of people with high levels of inflammation. I was always kind of skeptical of that explanation and thought it must be something else, but it shows up without fail and in the same spots for years now. Also, I never really noticed any pain in that specific spot until the last few months. So something must have been going on in there and now I’m starting to actually feel it, even outside of being on my period.