Masking and Tracking Small Area in Face

This will probably not be easy. The question may not so much the tracking, but how to cover that area seamlessly.

In a still image, one might use the rubber stamp tool to copy an adjacent area... in video we might be "painting" frame by frame, and in the end it might not look very good.

What plugin are we talking about?

I don't know the content, or the target audience, or even how egregious that "imperfection" in the video is.

You might want to consider embracing it and letting go, or perhaps devise some "creative" way to cover it, instead of trying to make it look like it was never there. Just saying.

If you'd be willing to share a small snippet or even a screenshot that illustrates the situation, maybe we can come up with better solutions. I understand of course if you can't or won't do that.