system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What are the requirements for a scar to form instead of a full recovery?
gpt
Your skin can only regenerate from the bottom up (the deepest layer) so if the wound is deep enough that you lose the bottom layer it can’t regenerate. If that happens, the connective tissue that lives underneath the skin has to grow into that space to heal up the area. That tissue, what we call a scar, is made up of entirely different cells than your skin so it doesn’t look the same or function the same as the skin it’s replacing.