Red bum

My baby is four weeks old and only gets breast milk. This morning for the first time she woke up with a fire red bottom. Front and back. It looks very sore and it breaks my heart! All I did differently then the previous four weeks was giving her a caraway supp last night because she had such tummy cramps and was bloated. Can that be the reason? Any idea how I can help her now besides leaving her naked and put bepanthen on?

Thanks for your help, mums and dads!