If this seems to be getting bigger, then it maybe an infection.
Next Steps
Apply ice 5 to 6 times a day, elevate the ankle over a couple of pillows while sleeping, take mild painkillers, take Tab Rutoheal (1 tablet thrice a day for 3 days) and Tab Taxim (200mg) (1 tablet twice a day for 3 days)
(provided you are not allergic to any of the above drugs!)