The best way to obtain a prescription is to contact the compounding pharmacy and ask them to send you or your doctor an order form, or technically a prescription template. This way all your doctor has to do is check the box and fax it. Most compounding pharmacies will provide prescription templates for specialty compounds like Scream Cream, as long as they make it.
Empower Pharmacy makes a lot of great compounds and can supply an order form for your doctor. If you do not have a doctor you can contact...or a similar clinic, which can provide a prescription for your wife through a doctor consultation over the phone.