Hello, Using cornflour is ok, it's actually dermatologically soothing and it soaks up moistness as well. You can get cornflour powder at the chemist right next to the baby powder.

Having said that, we never used it, preferring instead to use Amolin cream, which has a great combination of zinc, calamine, almond oil and petroleum jelly. Works well to soothe and also acts like a barrier cream. We have used it since then for any dry rashy skin things and it works well for that as well. We never had any nappy rash problems, even during teething. Hope this helps
:-)