it's normal mummy! our baby had this and his pd said to moisturize skin and pay particular attention to ths skin folds. it will resolve on its own eventually. we initially used a scented moisturizer but his skin reacted badly so had to switch to an unscented one.
It’s quite normal. My boy also had it. Gone when he was abt 5-6 months I think. Didn’t bring him to see doctor. Their skin is more sensitive at this point. Just rmb to keep her moisturised after bathing.