No, but it definitely does sound like stress, and not in the least surprising.
My bro used to tear his cuticles to pieces till they bled, when stressed over our mum (she had MH).
'Psychologically'. I wonder whether tongue chewing is because you have to endlessly 'bit your tongue' in the figurative sense, ie, stifle what you want to say (or perhaps yell?)(or even scream your head off????)
in a practical sense, are there any particular triggers that set you off, do you think?
Personally, I always think that when it comes to stress, we are like 'buckets'. If we pour in too much stress into ourselves, we start to fracture at the seams....the stress has to 'come out' somewhere, usually in unpleasant ways, as you are currenty experiencing.
When did you last have a break from caring?