Possible complications:

Abnormal shape of nose (pinched tip, polly beak, pug nose, scooped out nose; corrected by secondary surgery, often with an implant)
Airway obstruction
Anesthesia reaction
Asymmetry
Bleeding (may require nasal packing to control it)
Burst blood vessels
Depression
Discoloration
Extrusion (implants)
Infection (risk is less than 1%)
Signs of infection: pain, swelling, warmth, redness
Internal scar/adhesions
Keloid (heavy scar)
Loss of smell
Loss of structural support
Nerve Damage
Numbness
Pain
Perforation of septum
Permanent numbness (risk is less than 1%)
Reactions to medications
Septal hematoma
Sinusitis (treated with antibiotics and medications that shrink the nasal lining)
Skin irregularities
Skin necrosis or skin death (1500% more likely with smokers)
Slow healing
Swelling
Toxic Shock Syndrome
Wound Infection
Visible scar

When rhinoplasty is performed by a qualified plastic surgeon, complications are rare and are usually minor. However, all surgery has the risk of complications and undesirable outcomes. You can reduce your risks by closely following your surgeon's instructions both before and after surgery.

Burst Blood Vessels
After surgery, small burst blood vessels may appear as tiny red spots on the surface of the skin. These are usually small, but may be permanent. This rarely happens, but it is a possibility you should be aware of.

Bleeding
Bleeding may occur for up to four weeks after operation. The patient must resist any urge to blow or pick the nose to minimize bleeding.

Abnormal Shape
An abnormal shape of the nose may be due to an error during surgery or the patient not keeping their head elevated enough or sleeping on one side without a proper side. The nose can pull to one side if the cast does not support it properly. There are other factors that go beyond human control, as well.

Wound Infection
The rate of wound infection following rhinoplasty is less than 2%. Abscesses, cellulitis or granuloma may be treated with antibiotics and drainage. Use of an implant increases the chance of infection.

Risk of smoking
Smoking significantly reduces your body's circulation and vascularity. This means difficulty in bringing much needed oxygen to your tissues and greatly increases your risk for slow healing and other complications. It is important to stop smoking for at least 4 weeks before and after surgery.

Toxic Shock Syndrome
This is very rare, occurring in only 0.016% of rhinoplasty surgeries. However, if it does occur, the mortality rate is about 11%. Symptoms include fever, vomiting, diarrhea, and a sunburnlike rash.

According to an article authored by S. Valentine Fernandes on emedicine.com "the complication rate for nasal surgery varies from 4-18.8%. In individual hands, this rate generally falls as surgical experience accumulates. Skin and associated soft tissue complications occur in up to 10% of cases. According to estimates, severe systemic or life-threatening complications occur in 1.7-5% of rhinoplasty cases. Intracranial complications are rare."

The entire article is extremely informative and we highly recommend reading it. You can access it at: www.emedicine.com.