Anyone tried toppik? Do you know if it can block hair growth?

[Jane123]

When I apply Toppik fibers on my scalp, it usually just conceals the thinning areas with a light layer. However, near my part at the front of my head, the Toppik always clumps up directly on the scalp. At first it didn't bother me because it covers up the thinning area, but now I'm worried that hair can't grow through the fibers. In other words, at the area just adjacent to the part, there's usually a build-up of fibers (not that noticeable if you look at it, but I can definitely feel a bump of toppik when I touch that spot)- will this inhibit hair growth? I read that hair growth is controlled from inside, not above, but how can the hair grow up if there are these clumped up fibers on top? Thanks