It can be very upsetting to be close to someone who self-harms – but there are things you can do. The most important is to listen to them without judging them, or being critical. This can be very hard if you are upset – and perhaps angry – about what they are doing. Try to concentrate on them rather than your own feelings – although this can be difficult.
Do's

Do’s
Talk to them when they feel like self harming. Try to understand their feelings, and then move the conversation to other things.
Take some of the mystery out of self-harm by finding out about it.
Find out about getting help – maybe go with them to see someone.
Help them to think about their self-harm not as a shameful secret, but as a problem to be sorted out.

Dont's
Don'ts
Try to be their therapist – therapy is complicated and you have enough to deal with as their friend, partner or relative.
Expect them to stop overnight – it's difficult, and takes time and effort.
React strongly, with anger, hurt, or upset – this is likely to make them feel worse. Talk honestly about the effect it has on you, but do this calmly – in a way that shows how much you care for them.
Make them promise not to do it again, or make your involvement with them the basis for an agreement for stopping.
Make yourself responsible for their self-harm, or become the person who is supposed to stop them. You must get on with your own life as well. Make sure you talk to someone close to you, so you get some support.