I recently struck my shin on the metal edge of a wheelbarrow and within seconds it swelled up to the size of a golfball. Oddly enough, a few days later, the swelling is still present (a noticeable bump), although there's no real pain (except a mild tenderness around the swelling), no discomfort while walking on it, and no noticeable discoloration, etc. Given that the swelling has decreased marginally, I was just curious as to what has likely happened, given that I've never had such an injury before. Middle-aged, relatively good health. Thanks.