First thing to do is to try and make it happen eg key out and turn handlebars from side to side, apply front brake and push down on forks, etc.
Did the speedo light up, etc as when ignition is turned on or was it just the tacho sweep ?
Could be faulty speedo unit/damaged wiring but start with the speedo unit itself - dismantle and check for moisture/corrosion - then connector to the speedo unit:check for moisture/ corrosion - contact spray, blow out with compressed air and filll with dielectric grease - then ditto for ignition switch.