Is it likely I have intertrigo, or a normal yeast infection?

A few months ago, I was diagnosed with intertrigo in the anal area. That has been treated by a Nystatin cream given to me by the doctor, but now I am experiencing a faint itch, as well as the tell-tale crusty white flakes around my vagina and perineum. I have no real burning when I urinate so to speak, and the itch and inflammation I have is mild. I also have no discharge besides the normal discharge. What I am wondering if I could treat this with Monistat if it is in fact intertrigo? Or should I go about using the topical Nystatin cream given to me by my doctor? Would it be wise for me to use Monistat if this is in fact Intertrigo and not a normal yeast infection?