I’m so sorry to hear this. My bunny Bam had a reaction to the old myxi or the old RHV vaccine (they were given at the same time so we don’t know which it was), but he’s been doing very well on the newer Nobivac double vaccine. My Bam just got sores in his ears and around his eye though, but my vet agreed it was a reaction to the vaccine.
I’m glad the acute stage seems to be over. With neurologic incidents, it often takes some time (months) before full function is regained. With humans, you try to make them use the affected limb (often an arm/ hand) as much as they can, so the brain can “find” it again. Only time can tell if this is a permanent thing, but since he’s recovered so well and so swiftly from the first symptoms, I think chances are good that this too will improve.
This must have put much stress on him, so it’s not surprising if he’s a little subdued, but you should monitor him and make sure he eats and poops. Do you mind telling us what country you are in? (I’m interested in looking up the vaccine he was given.)