A slightly crooked nose can sometimes complement a face by making it more interesting. A very broken nose is just an eyesore. If you break your nose, you have two choices for resetting it: set it yourself, or have it reset by a doctor.
Unless you're experienced with broken noses already, it is highly recommended that you go with the second option. Otherwise, keep in mind that you must follow these steps as soon as possible after the injury happens. If you try even half an hour later, the swelling will make your job much more difficult. You'll be more likely to make it worse than to fix it. If it has already been half an hour, let the emergency room take care of it.
Sit down. This will be very painful and may cause dizziness or lightheadedness. You don't want to fall and reinjure yourself.
Blow your nose once into a thick towel. A lot of blood and mucous will likely come out, so Kleenex or toilet paper will not be up to the task
Make a triangle with both hands, placing all four finger pads against one another, with the palms sloping away from one another.
Place the apex of the triangle snugly at the top of your nose.
Take a deep breath in through your mouth.
While exhaling through your mouth, bring your palms together until your hands are moulded snugly (but not too tight) around your nose.
Slowly drag your hands straight down towards your chin in as straight a line a possible.
Check your work in a mirror. If the nose needs further straightening, repeat steps three through seven until it looks right.
Immediately apply ice to your nose to reduce swelling.
Take an over-the-counter pain reliever, preferably one with anti-inflammatory properties, such as aspirin or ibuprofen.
If you feel dizzy or nauseated after 10 minutes, go to the emergency room immediately. Dizziness and nausea are common reactions to the level of pain self-setting a broken nose will cause, but if they last more than 10 minutes go get checked out.
If your nose has been broken for a while, you may require surgery or rebreaking to straighten it. Needless to say, these are procedures to see a doctor about. Most of the time, they will be outpatient procedures from which you will recover in a week or less. If you can, go to the ER. The doctors there will splint your broken nose and pack it with gauze to stop the bleeding. They'll also give you prescription-level pain killers, which you'll be glad to have for the next few days.
Self-setting a broken nose is in no way preferable to getting proper medical attention. Your nose won't be as straight. You won't have access to proper medical equipment. An improperly set nose can be ugly and can even impair breathing. If at all possible, take your broken nose to the emergency room.