I've felt like that before. I think it may have to do with what area is cut. It has nothing to do with being a failure and everything to do with skin regeneration. My thighs have permanent scars but for the amount of cutting i've done there - many have faded and you have to squint to see them. However, i'm done scratches on my abdomen (very lightly - no blood really) and have what appears to be permanent scars. I've done my ankle to the same degree as my thigh and I can't get that scar to go away at all.

I won't tell you that your goal shouldn't be making scars because I've been in that situation and telling you won't make the urges go away. I will say be careful though because when I started carving I made some words and drawings that scarred. I thought I wanted them and now realize that I don't to the extent that i've scratched over one of them to rid of the scar (creating a new one) and constantly hide the other one. So just be careful because permanent means permanent. Feel better soon.