My Arab gelding has a scabby nose-it's in between his nostrils, but not at the end of his muzzle. He eats out of a feeder & there are no rocks in it & he doesn't pick around a lot on the ground. He does have a long blaze & it's pink & white in the scabby area. Could it be sunburn? If so, now what do I do? How do I get it to clear up? And what do I use to prevent further problems? He does have a shade cover, but does move around in his pen a lot.