Hi Adriana, sharing your experiences to try to help another person was very brave & kind of you! It should be acknowledged & appreciated.
All the hearts that people gave you say that too🧡 I was happy to read your last sentence 👍

Ok thank you. Will have a look at that later.

https://autism.org/causes-and-interventions-for...

Causes and Interventions for Self-Injury in Autism

https://autism.org/causes-and-interventions-for-self-injury-in-autism/

This might be a good place for a therapist to step in. They would have more knowledge about methods to implement for him instead of biting himself.

A way of coping with an answer he doesn't want to hear and/or accept.