if you go through Panerai service. You may find a local watchmaker who can work quicker.
Depends of course what is wrong with the watch and what model is it.
If it's a model with a basic ETA movement, then a good local watchmaker may be able to assist (if its a simply fix, like a mainspring). If it's an in-house movement, or a more complicated model, it should go to Panerai service and will take time...3-4 weeks minimum and up to 6 mos depending on the issue.