Girls, help! The child's diaper rash is not going away? We've tried ev…

Girls, help! The child's diaper rash is not going away? We've tried everything: Bepanthen, zinc paste, Sudocrem, talcum powder, Neo-Cortin...no results at all? Only diapers for walks and at night (we change them with every feeding) I think it's better to go see a doctor, maybe there's some kind of fungus...I don't know what to do anymore