DS aged 8 has started to punch and hurt himself when he is angry or upset - hard enough to leave bruises. The other day he went to the drawer in the kitchen and tried to grab a table knife. We have a magnet with his school photo on and he has tried to smash and destroy it a few times saying he hates himself.
In the past it has been when I've told him off about something. He hates me being cross with him and will escalate the behaviour until I give him a hug and tell him it's ok.
Things have come to a head recently over school work as a few times he's had to do things again or been told off over rushing so that he can watch cartoons.
He doesn't have any SEN or other issues that I'm aware of. He's always been an anxious child. He is very caring and loving but does have a manipulative streak so I'm not sure what to do. I don't want him to hurt himself but sometimes I do need to be firm with him!