Diaper rash problems


So last week, my 8 month old had been eating foods she’s had before. Mac n cheese and some chicken, mashed potatoes, yogurt. All the sudden she poops and it makes her all red down there, I mean apple red and it had heat to it. It turned to blisters and my diaper cream was working and was almost gone today but she had ANOTHER poop today that did that. Bright red and hot and she just cried in pain. She did have hamburger and corn and beans and some mandarin oranges but she’s had that like 4 days in a row but the oranges only 3 days but she LOVES those. Any idea on what could be doing this and how to prevent? I feel so bad for my baby 😢