bruising

I am a 70 year old woman and 6 days ago my left leg was hurting and became more and more painful as the day progressed. The next day it had become even more painful so thinking I had pulled a muscle or it was my neuropathy or  arthritis I applied Voltoren Gel.When I looked at my leg, I had a huge purple bruise that covered most of the back of my knee going up my thigh and has now bruised down the side of my calf around to the front of my calf and is swelling and painful and the bruising continues to spread. It is unexplained as I don't remember injuring it at all. Thank if you can answer this for me as I feel like I'd have to see a doctor.

[Thomas D Schiano, MD]

please see a doctor right away about this