“Swollen legs?”

I am a 58 year old female. Four weeks ago I noticed that my feet were swollen with no pain. Subsequently, as of today, the swelling has reached my thighs and is very painful. My lower back now is causing severe pain, like a pinched nerve. Today I must have scrapped my left leg through my jeans. On examination, there was no blood just clear fluid streaming down to the point where jeans for that leg was soaked. Any ideas on what's happening?

Caroline
Canton, Ohio