When we lived in Aden, all the kids when they first came out to live there got Septic Prickly Heat (the kids were not allowed to go to school until it was gone) we were all covered in blue and yellow stuff they painted on at Sick Quarters, my mum decided to use Calamine Lotion instead, it was called Crookes Lacto Calamine lotion it was not like the Calamine Lotion you get in Boots today
Heres a pic
you can still get it but its been updated and Aloe Vera has been added.
Anyway it did the trick far quicker then the hideous ointment.
You can get Calamine powder and make your own lotion perhaps mixing it with Aloe Vera Gel so it is not so drying, I make my own face masks with it. You can get a big tub of it from amazon.