Soak an old, clean cloth in cider vinegar and apply it to your ankle for 20 minutes at a time, every couple of hours. You can also make a paste out of aspirin and water and apply it a couple of times a day. Leave the aspirin paste on for 30 minutes or so, and then rinse it off. This will help the trapped blood dissipate much more quickly.
There are several treatment methods that you can use on your bruise to make it heal faster and be less visible. You can use witchhazel to make it heal faster and heparin based cream to make the bruises less visible. Get more advice from a skilled doctor.