Bruises that spread days after infliction?

[selkie]

I had a very large bite bruise on my inner thigh and about two or three days afterward it sort of spread and seemed to ooze downward into an upside down teardrop shape. The same thing happened once when I fell at work and banged my upper arm on the edge of a counter.

This has only happened twice so I'm not sure what to think about it and I was wondering why it happens? Does it have something to do with the amount of blood under the skin or gravity or...?

[Ozme52]

Often, the delay in spreading is due to swelling, and only as the swelling subsides is there "room" for the bruising to spread.

Why downwards? You called it. Gravity.

Lividity (how blood pools downward within a newly dead body) is one way how forensic scientists know whether a body has been moved. Because gravity causes the settling blood on the downside of the body.

[Polecat]

It would only be worrisome if you started to bruise more easily and the bruises tended to become larger. It could signal a bleeding disorder or something worse. A simple blood test would provide the answer if that was the case.