I cut myself with a piece of broken mirror?

First off, you need to try to find another outlet for your stress. Physically harming your own body will accomplish nothing but permanently damage your body. Second, yes they probably are scars. When dermal tissue heals, new cells are produced to join the back together. Scabs only form if the wound requires something to pull the edges together. If it was a clean cut, then there won't be a scab. So yes, it is probably a scar. My advice would be to go to your local pharmacy and get some stuff called Bio oil. It is somewhat expensive, but it is the leading product on the market to remove scars and stretch marks.