We have an 8 yr. Old paint (tobiano), who has had a bump or knot at the end of his muzzle for almost 2 months now..I thought it was a sting or bite, but it's still there. He also has a few small bumps that have recently surfaced since the heat index has been above 100. His muzzle is white so he is sensitive to the sun & has to wear sunblock sometimes. Has anybody else experienced this skin disorder or bites? He's such a pretty boy, but sure would look better without the bumps.