Hebe has a nasty scabby patch on her neck, behind the ear, about the size of a 50 p. piece. The scabs look granular, like demarara sugar, and they rub off easily, leaving bare skin. They don't seem to be itchy or painful. It looks rather like mud fever - we had a bit of that earlier, in the winter, but that healed up by itself. Anyone have any idea what this might be, please?