P.M.
It is possible that she is allergic to some of the other "stuff" in the sunscreen, fragrance, etc.
I use a product called SolBar. It is not at all creamy, it is a thin watery gel. It absorbs immediately into skin and doesn't leave you sticky.
You can get it without a prescription, but most pharmacies don't stock it, you'll have to order it, or perhaps you can find it online.