I also used chewy sensory toys, they are great. They come in so many different designs and colors

chewy sensory toys , there are ring shaped or necklace shapes etc

My son did this with his shirts! Holes everywhere! He wore the same 4-5 shirts(all green, everything HAS to be green). He stopped after about a year. He chewed on his chew toys too. It will be ok mama!

Thank you.

My daughter does the same thing. We cannot stop her either. The only thing we do is try to offer different types of sensory input and help her when we can to come out of a meltdown faster. It’s tough to watch your child hurt themselves. She has calluses now where she bites the most and I moisturize her hands.
If you have ABA therapists, they may be able to give you more specific things to try that relate to your child.
In the end I would say that the SIBs are one of the toughest things that present in people with autism. What those SIBs look like changes over time and intensity will vary. In the end as I stated the best thing to do is try to manage what happens before, during and after as you will not be able to actively stop the biting itself while it is occurring. It will be trial and error.