Yep.  I use the bullfrog spray on my appy mare.  It's liquid and sprays like water, but works great.  Just be careful not to get it in the eyes.  Or I have seen a wipe with sunblock, or was that bug spray?

Below s a quote from a lady on another message board that owns a horse with a white face; note she says she USED to use sunblocker and the reason she quit:

To prevent sunburn -- I use to use sunblocker 45 in the suntan lotion.  I used it everyday.  Problem was it clogged the pores of one of my horses and the hair started falling out on his face.  He is a paint with pink skin and blue eyes.  I switched to zinc oxide - use it everyday and neither of my horses have had a sunburn nor does their hair fall out.  I use the Walmart brand and it's $1.87/tube -

EDITED TO ADD:  I wear fly masks on my horses every day.  I keep them one or two fingers loose (depending whose head), take them off every night and wash them in the washer on slow cycle for the least amount of minutes my washer allows.  I have four horses and no one has any rub issues

i have a paint filly that has a totally white face/nose and two glass blue eyes.  i keep her up in the summer months during the day, with a fly mask on.  i then turn her out at night.  during the day, if i ride her for a mjority of the day, i use regular ole sunblock on her nose only.  when it cools off, and winter comes around, she gets turned out during the day and is in at night.  i also make sure that when i show her, and use "grease" on her nose/eyes/ears that i remember to wash it off so she wont get burned. 

i have never had a horse lose hair, or get rubbed from a fly mask.  make sure you arent putting it on too tight.  i really like the kensington brand much better than most others.  it has a double velcro closure, and stays on even when i leave plenty of room as to not rub noses.  hope this helps.