8 months ago i dropped some timber that hit my shin leaving me with a nasty scar about 2 to 3 inches long down the length of my shin, recently i knocked the same shin really badly and was in some discomfort. now roughly 2 and a half weeks later swelling has reappeared with tenderness to the swelling and shin bone along with 2 red bands one where the impact occured and one nearer to my ankle. my ankle bone can not be seen due to the swelling either i do a lot of long hours on my feet in my line of work but find that although it is sore to be upright it is not impossiable, what may be the cause?