That is a serious scar in a bad place. It may always have some issues with chapping and have a weak spot. Id apply something like vit. E oil or corona directly to the skin and encourage healthy skin as best you can. Bad scars can sometimes just have issues like that.
Id also have an X ray done if you feel froggy, because if the bone was shattered a bit, bone chips could work their way out for years to come. It probably wouldnt cause a lameness at all but would cause recurring sores to happen as they work their way out. Kinda like shrapnel.