My Foot Has Been Swollen Up For Almost 2 Months

My foot has been swollen up for almost 2 months now and some part is having a black color, and the pains comes at night when my body is relaxed....I have been to the hospital ad they took my blood sample and did a test and also xray to see what the problem was....but ufortunately the doctor came back and said they couldn't find anything....i have to ask him to give me some antibiotic prescribtion in case it an infection.....i checked similar cases online and i thought it was Venous insufficiency, but the doctor could not confirm what it was.....So i need help to get this swolled down and get my skin color back to normal.