I have a ganglion cyst. how long until i'm off from work?

Depends on treatment: Ganglions are very common & often asymptomatic unless they exert pressure on a tendon, nerve or interfere with joint motion. Observation (ignoring), compression technique (hit with bible), and even aspiration can have a high persistence/recurrence rate > 80%. Surgical excision can have a <15% recurrence rate that can be even lowered with casting, which may require 2-3 weeks off depending on job.

Depends: What kind of work? Heavy work involving use of hands like construction, driving, or even prolonged computer use may need at least a week off.