Woops, abright does have a point. An important one, the wire may have been damaged badly preventing it from carrying the proper current to the light.
The flickering is likely caused by the individual strands coming in and out of contact with each other.
If you have some solder and a gun then that would be the best fix. Make a clean cut and slide some heat shrink over one of the ends and push it out of the way. Strip some of the wire on both ends and solder the two pieces back together. Slide the heat shrink over the joint and heat it up till it shrinks. That will rejoin all the strands again as new.