I need some help, for my son and family

Hello, its been a while since i posted and things have been manageable but now im very desperate so reaching out.
I have a child who is 7, he has a diagnosis of asd. Who seems to go through good times and bad times with how he is thinking. We are at a bad time right now. He has a tenancy to self harm. So we put away all the sharp things but this time he used a pen to stab his thigh he has 9 separate bruises. I can't imagen how hard he has done this. He used pins before to 'stab' himself. Scissors to cut and he often hits himself with his hand or on walls. He uses sticks at the park to scratch his himself.
He masks at school but comes home and grabs thorns and will start kicking things.
School see no issues but home is really hard.
He talks about brain voices and how they fight each other and how he can see them and flick through them and choose which one he wants to be. At the the minute all we are is 'angry' voice where he ' stabbed, hits, pinches himself'. In his words.
We went to the park today and the child we were with he said he would 'stab the fat pig in the eye and kill him' I have reached out to CAHMS and he was seen by the mental health team. During this time he knocked his sisters teeth out and self harmed, but things got better for about 6 weeks, so we got discharged.
Now we are back to square one, he cut up his bedding and fairy lights. I worry what if he cut another wire?
What if he stabs himself with something that isn't a pen? Is this ASD? Is there any more I can do? We are back with the mental health team. But have a wait again.
His behaviour swings so much. A few weeks calmer and a few weeks in this really hard stage
Is this what happens with other children?
What can I do?
As a mum, I can't sleep, I'm so so stressed I feel sick. I just want to make sure I don't find blood on his sheets and bruises on him that are self inflicted.
Thank you anyone for any help. Or any suggestions.
We have had all the Early Help, enabling families, lego therapy, ELSA emotional literacy, OT reports, and as much as I can possible get for my child. Unless I'm missing something?
Thank you xxxe