I told you: the semen strands are sticking to her
scalp. The size, shape, and length of the hair is irrelevant. SDT does not check it. It
could, but it does not.
The only significant factor is the
layering of the hair. If hair strands are drawn on a high layer, then they'll tend to obscure any semen strands which become stuck on the scalp. If the entire hairstyle is drawn onto a low layer, then semen will be visible "on top of" the hair.