Definitely purchase a flymask and consider sunscreen. The neck probably won't need sunscreen unless she is very thin coated and you can see the skin through the hair. However, when I show my extreme white paint (see avatar) outside and he is going to sweat, the sweat makes his skin vulnerable to the sun and I use a spray on sunscreen.
My white-nosed horses get slathered with sunscreen before they go out if the UV index is going to be anything higher than 2. The one I like best is Hawaiian Tropic Sport 60+ It seems to absorb and dry the best, cheaper brands don't seem to stay on as well or last as long. You can look into the long-nosed flymasks as well. I bought the kensington "bug eye" with optional nose piece. Seems like a great idea, but I found that the eyes are constantly being popped in :( The only long nosed one I like so far is the cashel brand, but it definitely doesn't fit as well as the farnam supermasks do.