Girls, good night everyone My daughter has severe diarrhea, the…

Girls, good night everyone My daughter has severe diarrhea, the pediatrician prescribed piobacteiophage and Fertal. How do we deal with it? Has anyone experienced this? Strong diaper rash, I don't know what to help her with, she cries when changing diapers and how does she go to the toilet... Sudocrem, Bepanthen and powder don't help, what did you use?