Oh no. Looks similar to my baby too. Might consider cooling clothes like cotton (mine are mothercare short sleeve). and watch out especially when using baby carrier as the heat from body gets trapped. Dont overdress baby on warm days like socks pants hats all too.
If its not too bad can moisturise liberally after each bath (currently on QV moisturiser). Try to avoid steroids for now first. unless super serious and dr recommended
in the end i found out my baby had eczema so heat and friction just made things worse. Can try to rule out fungal infections too or even breastmilk or saliva dripping.