Suggest Treatment For Swelling And Pain On Leg

2 weeks ago my left leg became painful and swollen with a greenish look developing under the skin from knee to ankle. after 4 days i noticed 3 red sore spots at ankle level. the greenish look became darker in color and is painful. What do you think is happening as I was told by my Dr. just to take tylenol if it gets too sore. i am on warfarin5 mg and INR is 3.0
Thank you