I bite the insides of lips and cheeks a lot, sometimes when I get the feeling I'll chew some gum instead. Of course I often forget to this tho, but it does help.

I pick my fingers to the point they bleed I find fidget toys help like tangles and for bitting the inside of your mouth/ your lips you could try gum?

i chew things like plastic (ie bits of pen lids) but i also tend to swallow the plastic and idk how good for you that is

Stim toys (thinking about the chew ones specifically), gum, mints. Addressing any underlying causes you can if possible. That’s about all I can think of. It’s definitely a struggle and I really haven’t found anything that truly works well unfortunately

Sometimes Ice can help, you can let it melt in your mouth or you can chew it, it might not work for some but it could do for others. Mainly for when your at home, or maybe try have a chewy sweet to carry round like starbursts as you still get to chew on something and bite x