My foot got stood on by metal studs when playing football, it still hurts 9 hours later. It hurt at the time but I could carry on playing the game, I can weight bare but it is sore to touch and hurts when I curl my toes up. It is on the outside of my right foot, just after my ankle. There is no redness, other than the stud marks, and no swelling. Is this a muscle injury and are there any exercises I can do to heal it?