Sudden diaper rash

Hi mummies, is this diaper rash? When i picked my baby up from ifc teacher told me he got diaper rash which was a shock to me he barely had any diaper rash before. Other than his butthole red cause always poop. When i came back to shower him, both his inner thigh was super red 😭 feel like crying seeing this. He was perfectly fine that morning, skin was fine. Is diaper rash normal ? What product should i use ? Im currently using pureen diaper cream and huggis naturemade. I dont think its the diaper as he’s been using it since birth.