If the cable feels like it's still connected---have an assistant pull the knob while you press down on the nose of the hood--try to work it up and down--even using a bit of force upward. If that works--lube everthing well and give it a test. The "quarter moon" section of the latch should retract all the way when the cable is pulled.
If that didn't work you can gain access to the underside of the latch by removing the plastic panel between the bumper and the undercarraige. From there you can lube, bang, pull, push, etc. on the works. -- Dave