Kipper, I know that a lot of the time there is bruising on your leg after surgery. It definitely goes away, but not before you get some lovely neon colors going on down there.
Because I'm on Warfarin for my heart, my cardiologist tells me to watch for bleeding that can come when your blood gets too thin. I've never had the problem, but they say unexplained bruises (not like those associated with surgery or an injection site or a "bonk" you might have gotten) or lots of small red dots on your skin would be a warning that should cause you to have someone check your blood numbers. This is why they like to check you so often when taking Warfarin.
Being on it for years, I've found that consistency in your diet is the best way to keep things on an even keel. Certain foods (spinach, broccoli, cabbage, Brussels sprouts, Romaine lettuce are a few) contain Vitamin K that can cause a change (thickening) in your blood. And things like pain meds and wine and booze can make it go the other way (thinning). So no bingeing on spinach or whiskey, okay? (a little humor)