Most cuts that reach the deep layer of skin (dermis) will cause scarring; it’s just a matter of how obvious they are when they heal. Scar tissue is a particular type of tissue (collagen fibers) that is different from the cells surrounding it and will typically be a whitish color.
If a scar is small, you may not notice it at all among the hair or against the skin surrounding it. If a scar is large or jagged, the collagen fibers will be more obvious. There are also some cases where the body will produce too much collagen in response to the damage, which results in lumpy scars called hypertrophic or keloid scars.
There are a number of factors that go into whether a cut will leave a scar.
hypertrophic scars or keloid scars are raised scars that come from deeper cuts, where your body spams collagen proteins haphazardly to try to get the wound closed as quickly as possible.
If the cut is a regular shape it is easier to heal. surgery incisions are usually straight lines made with a very sharp scalpel so as not to tear the edges and create any ragged flaps of skin that will be difficult to heal. Some weapons are created specifically to have a nasty shape that will create wounds that are difficult to heal. Irregular wounds are more likely to scar.
Also cleanliness can determine scarring. if your wound is clean there is much less likelihood that it will scar.
basically, scarring is your body freaking out over a wound and just throwing material at it to get it closed. if a wound is clean, shallow, and an easy shape to heal, then your body won’t spit extra proteins at it.