There are some pretty cool photos of this online if you look them up. It actually looks something like scarification which is kind of weird really, but it must be kind of fun to play with. I mean, if it's not too irritating with your skin.
I can remember doing this on purpose when I was a teenage, trying to make patterns on my skin by pressing hard with my nails. And I still sometimes get patterns on my skin when I get out of bed or remove tight clothing. I guess this is just an extreme version of that.