Go to the opd of any dental college after lockdown. The extent of your lower jaw to upper jaw difference in not known,since you haven't included any photograph with your query. Moreso, your condition needs a thorough examination along with radiograph of your oro-nasal structure.
Nothing to worry, you will get the required treatment as per the extent of your problem.
Next Steps
You might get treated either by an orthodontist or oral surgeon ( if the extent of problem is too noticeable).
Health Tips
As i said, the extent of your condition will define the time your condition will take to heal. So, nothing much can be said without examination.