i need help with my chewing stim

i’m a autistic and have ADD and i have a really bad chewing stim i bite on my cheeks my lips and piercings and it is ruining my teeth cheeks ect. i also over eat to regulate because i feel like i need to chew something i have tried using chewing gum but it doesn’t work i have looked into buying one of the chew jewellery but they all look too hard please help lol