That would be the third and bottom layer of the skin and it is called the subcutaneous layer. It is made mostly of fat and helps your body stay warm and absorb shocks, like if you bang into something or fall down. The subcutaneous layer also helps hold your skin to all the tissues underneath it. It’s composed of fatty tissues.
As a side note I would like to add: if you are harming yourself please seek help from a friend or a therapist, especially if you are cutting deep enough to see this layer. If you don’t have a friend to talk to, you can message me. I will listen~ Please stay safe.
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