If i have a palsy in one eye, how should i wear a patch?

Eye should be closed: Bell's palsy is a condition where facial nerve paralysis may result in an eye that cannot close fully. A patch may be prescribed to keep the lid closed, and prevent the eye (and cornea) from dangerously drying out. Alternatively skin tape can be used to patch the eye closed at night, without a patch.

Eye patch: I am not sure if you are wearing for bell's palsy, amblyopia, or extraocular muscle palsy. In all cases the length of time can be quite variable, and you should really be seeing an ophthamologist.