I always have the bottom part of my horses' legs clipped, from the hock and knee down. I'll clip about once a month to keep the legs looking clean for shows. You can faintly see the clipped/un-clipped line on my horse in my profile pic.
It shouldn't be an issue if you blended the lines in around the knees and hocks, it will look "normal" in a few weeks or months. Even if you left a hard edge, the hair will grow back on the lower legs in short order (max 2 mos). If you clip her body or upper legs after winter solstice, she will have lines. At this point in the year it's either clip her entire body head to toe, or just leave it and wait for her to shed out.
They say money doesn't buy happiness -- well happiness doesn't buy horses!