You must have developed hematoma
(blood collection in tissue), which has not resolved so far. If it is not progressing and not giving much discomfort, you can wait for a few more days. An X-ray can be obtained right now to rule out some bone injury
If everything is fine, in due course of time it will subside.
Otherwise consult a doctor.
Dr. Ajit Singh Kulhari
MD - Skin & VD