you need 7h or more of sleep regularly or you'll get neural damage in the long run. i'm talking tinnitus, spasms, halluzinations, etc. a few days less per month won't be a problem
to some degree, yes. like hallucinations or eye twitching will usuallly disappear after one or two nights of 7+ hours of sleep. tinnitus can take several days to disappear.
Good to know. I definitely had some minor auditory hallucinations or spasms come and go depending on how badly I managed my sleep schedule and I never really thought about that. I think the tinnitus is mostly actual physical damages because I wanted to rawdog some metal concerts when I was younger though.