I personally wouldn't worry about it unless the lameness is very persistent. That is a pretty small splint and after it is all healed, you probably won't even notice that it's there. I would go ahead and turn her out like normal and not even worry about the boots or wraps (I would be afraid of her hanging them on something). I would also avoid the bute. If she is ouchy, that is her body's way of telling her to take it easy and protect that injury. If she is buted and not feeling that pain, she could get to running and playing and hurt herself worse. My boy Denny is one of those that has suffered multiple splint fractures in his life. Some people say that certain conformation will make a horse more prone to it but IDK how true that is. His started as one lump about the size of Jynx's many years ago and they just seemed to multiply on both front legs. I am very careful to keep boots on him when I ride but that isn't feasable when he's turned out to pasture. It may look ugly but he has never taken a lame step. Some horses do and others don't. I think it depends on their individual pain tolerance and how the initial injury occured.
You can see the bony growths that start nearly at the knees and continue midway down the cannon bone.