I dont know how many have tried Underwoods. If it is on an area they wont lick off or if you have an E collar you just spray it on and then dust it with baking powder. then you never wash it off you just spray over what's on there and dust it again. I do it twice a day and it will heal the worst cuts with almost no scarring. I have seen wounds on horses you could stick your head in healed with this stuff and now no scar. anyway its worth checking out.
here is their link:
http://www.underwoodhorsemedicine.com/