About 9 months ago I acquired a very large and painful bruise on my left leg which covered the entirety of the outside of my thigh from my hip to knee. After several weeks this disappeared but since then it has been replaced by a large, but painless swelling of what just seems to be a sac of liquid. There is no colouration and no pain at all but I'm just enquiring as to whether it would be a problem possibly in the future and whether I should get it looked at. I am a 17 year old male. Thanks