My way would be to duplicate your video layer, and garbage matt out a similar 'hair section' then shift the position of this layer - effectively 'covering' the white spot on the underlying layer.
It's quite a small area, so I doubt it'll be that noticeable.
Your other option is painful frame by frame rotoscoping
Probably the easiest way to do that would be to Duplicate the Clip, placing the dupe above the original. Then, use say the 8, or 16 Point Garbage Matte to outline a similar patch of hair, nearby. Then, use the fixed Effect>Motion>Position, to "nudge" that dupe over to cover the fluff. Play the Clip, and make sure that you do not need to Keyframe that little bit of the dupe to keep the fluff covered. I would make sure that I had an irregular shape in the Garbage Matte, so that you do not have any horizontal sides, or vertical sides - irregular will be less likely to show.
If you find that you need a soft-edged Matte, then the Track Matte Keying would do that for you.
PS - for complete "retouching" of the hair, you could use the Clone Tool in AE, or use Rotoscoping, and do the work in PS, but I think you can do what you need, without that much work.
[Edit] Looks like Adam hit the Post Reply key more quickly - of course I had to log back in twice, just to post - love the way the forum is heading "south... " NOT!
You can replace the clip with an After Effects Comp and clone it out. Very simple.
After Effects would make quick work of this, but here's a possibility using just Premiere Pro effects:
- Put your video clip on Video 1, and then a copy of it directly above on Video 2. Temporarily disable the Video 1 clip, or turn off visibility for the Video 1 track.
- Drop the Circle effect on the Video 2 clip. Position and change the parameters of the effect to draw a small circle covering the fluff. Make the radius as small as possible, and add feather to soften the edges of the circle. Finally, set the mode to Stencil Alpha; this will create a cutout of the fluff.
- Using the Center property of the Circle effect, turn on the stopwatch and animate the circle cutout to follow the fluff. Start at the first frame and move through in increments. You may need a few keyframes, but there is no need to be too exact. Try and keep the circle centered on the fluff.
- Turn the Video 1 clip/track back on. It should look like you've done nothing at all
- Add the Offset effect BEFORE the Circle effect on the Video 2 clip. Now, change its "Shift Center To" parameter to slide the "patch" around to pick up another section of the hair. You shouldn't have to go too far if you kept the circle "patch" small.
You may need to tweak the parameters of the various effects to get it just right. You might also try setting the Blending Mode of the Video 2 clip to Darken or Multiply, which should effectively limit the patch to just the light portion that is the fluff.