I got tremor 3 months into long covid. It was internal, not visible. They worsened from being just at night and just along my spine to being full body all the time. I finally saw a neurologist who prescribed 100 mg Gabapentin 2 x a day - to quiet a Neurological system that was "whipped up". It took two days to eliminate the vibrations by 99% . So grateful. It was uncomfortable and terrifying and doctor after doctor wouldn't address it. Tremor or vibrations or buzzing is now in the list of common long covid symptoms compiled by Yale.