Can I ask what kind of scars they are? I ask because I had a friend who worked in a food shop that had ovens she would always burn herself on - they looked horrid and she covered them because she was embarrassed. But it was genuinely an accident.

Why people cut themselves? The girls have given you some of the more common reasons. It can also be used as a way for them to feel in control - usually when something is going "wrong" in their world (assault, divorce, moving house, failing school) - they have no control over whatever the situation is so they cut to be in control of their pain.

Some people cut because they believe they are evil, or their blood is filled with poison and so cutting themselves and bleeding is the only way to rid themselves of the evil/poison.

Some people self harm because they have auditory delusions which tell them to self harm (I've seen cutting, burning, punching, and even stabbing).

Even in those who are attention seeking - you have to ask WHY do they want the attention? Is it because something is happening in their world that they don't feel they can speak about but want someone to notice? Is it a cry for help and a sign of such a deep depression they are at risk of more serious self harm (suicide)?

As the others have said, it isn't always obvious. And parents don't always know - how many parents would see their child with almost no clothes on? Usually cuts are reasonably superficial and don't bleed heavily nor cause any significant alteration to behavior in the sense of causing a limp. However, this sort of behaviour is not usually isolated - there are often other behavior changes present... elusiveness, secrecy, becoming withdrawn, sudden mood changes are all common but not necessarily typical to every case.

Encourage your son to talk with someone he trusts at school about this. But keep in mind, he will need support from you because once he tells a staff member - they are OBLIGED to report it to the relevant authority (DHS in Vic) who have to investigate it. It could cause friction between him and this girl and he may need support from you to cope with this. I don't intend you to deter him from talking to a staff member at school (rather the opposite), but hope to ready you for the difficult road he could face.

HTH

MG