Most likely your camera has to be replaced. Is this the front or back camera?
You can buy the front and/or back camera from here, note that these are compatible with the SM-N9005 phone model.
Galaxy Note 3 Front Camera (Verizon/Sprint)
Galaxy Note 3 Rear Camera (Verizon/Sprint)
Guide on how to replace the rear camera:
Samsung Galaxy Note 3 Rear Facing Camera Replacement
You can use the same guide to help replace the front camera. The front camera has a black metal plate behind it to hold it in place. You can easily lift the black metal plate up with some prying tool. The front camera should come out easily without much force.