What Causes Swelling In The Legs?

Last Sat. night, I suffered blunt force trauma to the back of my leg (upper leg) & I couldn't walk for 2 days...the bruising is receding but the area that took the most trauma looks swollen but feels somewhat like jelly. It isn't "hard" to touch it actually moves around. What could this be & is it something I should have a Dr. look at?? I'm uninsured & don't want to incur any more bills if possible.