First of all congratulations on arrival of a new baby. diaper rashes very common particularly in small babies when urine and stool stays there for a long time. Siloderm mixi has antifungal,antibiotics and skin barrier creams. all you needed in the first place was only skin barrier rather than putting antibiotic and antifungal creams. So right now instead of putting another cream it is better to check with a pediatrician . skin rashes has to be shown.  it is not a good idea to treat them over phone particularly when you have already treated with combination of all medicines.