it is definitely fluid build up of some sort. my concern would be the edema might or might not be related to what happened. I would go to the Dr. to see if it could be a thrombus (blood clot), or maybe cellulitis, in which case you will need some iv antibiotics. Dont put it off to long. If the area is tender to the touch, red, edematous (swollen). I would hace some level of concern. In a case that it is cellulitis, to long w/o treatment could lead to permanent damage. Think about it this way, to find out that it is nothing at all is alot less expensive than finding out to late that it could have been resolved easily if caught early enough.