This definitely needs medical attention. A blood clot can easily dislodge from the affected vein/artery and travel to the lungs (pulmonary embolism), heart (heart attack), or brain (stroke), all of which can be fatal. I had an extensive blood clot from my left knee to abdomen. I was hospitalized and received daily low dose heparin shots in my stomach. I had a catheter inserted into the affected blood vessel, through which tPA (Tissue Plasminogen Activator - which is a clot-busting drug) was administered. The clot was then sucked out using a vacuum-like instrument. It took a few tries to get it all, but it worked and I am clot free! This is pretty non-invasive and you are awake during the procedure. Hope this helps!