Answer:
Sebaceous filaments.
See this post:
http://www.acne.org/messageboard/Sebaceous-filaments-t246249.html
"Those are not blackheads in your nose…..most of the time.
Almost every day I get clients at my acne clinic that think they have blackheads on their nose. I know that what they see in their nose looks just like blackheads, but it is not. Those are what are called sebaceous filaments. They are basically the oil glands on your nose and in the chin area just below the lower lip. They are meant to be there and will never go away. Even if extracted, it still looks the same and it fills right back up again a week later.
Once in a while, someone actually will have blackheads in their nose. The picture below shows a client of mine who has blackheads in between the sebaceous filaments. Those definitely need to be extracted.
So, my rule of thumb is, if all the so-called "blackheads" in your nose are all the same size, then they are not blackheads. If, however, you have a "blackhead" that is bigger than the rest of the other "blackheads" in the nose, then it really is a blackhead and not just another sebaceous filament."