The photos are graphic for the link. People are cutting themselves in solidarity with Amber Heard.
In the Old Testament, self-mutilation was a common practice among false religions. First Kings 18:24–29 describes a ritual in which those who worshiped the false god Baal slashed themselves with swords and spears, as was their custom. Because of the traditions of pagans, God made a law against this sort of practice. Leviticus 19:28 says, "Do not cut your bodies for the dead or put tattoo marks on yourselves. I am the LORD." In the New Testament, cutting oneself was associated with someone who was possessed by demons (Mark 5:2–5). It was characteristic of behavior caused by evil spirits.
This is horrible and people are mentally ill, possessed or both.
If you notice, the one arm has lots of healed scars from cutting in the past. This trend is horrible -- it's only encouraging people to cut themselves who already have a mental health problem to begin with.