Unfortunately, it's not Gnats. We have flies but they are kept at bay with daily application of fly spray.
We're in 110+°F during the days and in the 90s at night.
I'm really careful what I apply because it can easily fry on the horses.
The Medicated Wound Care has an Insect Barrier. I like it because you can put it directly on open cuts and not have to worry about the flies.
One of the other horses had a horrible case on his face where he had rubbed lots of little spots and I couldn't keep the flies out long enough to heal. This ointment really helped and cleared it up in two weeks.
The hair loss doesn't have a specific point - there's no rubs to really apply wound care to, and slathering his face will go through the ointment too quickly for cost (as well as potentially causing issues due to the heat and his ability to sweat).
I really appreciate the feedback.