How long could swelling on a nose take to go away?

Just like rhinoplasty, swelling on the nose after trauma can take 6-12 months to go away completely. 

If you had nasal trauma with a nose-bleed, and shiners, you may have broken your nose. The diagnosis of a nasal fracture is best made on examination, and an in-office closed reduction of a nasal fracture with local anesthetic may be performed within ten days of the trauma. See your rhinoplasty specialists as soon as possible. Wishing you well. Dr Joseph

 A crooked nose can be fixed at any time after the injury, but it's usually best to wait a few weeks to let the swelling subside before going in and resetting the nasal bones straight. Also important to evaluate the septum to make sure it's not fractured and deviated as well.   At the time of the examination,  the upper lateral cartilages need to be checked to see if they have been dislocated off the nasal bones as well. For many examples of  straightening a crooked nose, please see link and the video below