nail biting

i have been biting my nails since i was a child (i’m now 20) and am fairly sure i do it as a form of stimming/self soothing, it’s bad to the point that if i go to bite my nails and there isn’t anything to get a hold of i get frustrated, upset, and distressed.

i’ve found that using a tangle to keep my hands busy works most of the time as i don’t really like to have stubby bitten down nails but recently even redirecting myself doesn’t stop me … i’m very aware that it’s gross and not exactly pleasant but i’m not sure what else i can do to try and stop myself. 

wondering whether it’s less of a hands thing and more of a chewing/biting stim? not sure if that makes any sense.

is anyone else a chronic nail biter due to autism … is this a common thing?