Election officials nationwide assure there's no need to panic, and indeed there are processes in place to deal with the unlikely eventuality that your vote-by-mail ballot was received, opened, verified, and tallied.
Below are specific instructions for voters in Miami-Dade, Broward, and Palm Beach counties to track a ballot once it's been mailed or dropped off at an early voting location — and what to do if there's a problem with your ballot at the eleventh hour.
Note: These instructions are tailored for South Florida voters; if you live in a different county, you should consult the website of your Supervisor of Elections.

The voter information tool allows you to see the status of your ballot from requested to sent, received, and counted. The screenshot above shows what you'll see if everything went as planned.
Screenshot via Supervisor of Elections
Miami-Dade County
Miami-Dade County's voter information tool allows you to track the status of your mail-in ballot. All you need to do is provide your first name, last name, and date of birth.Broward County
Broward County provides a similar tool to track of your ballot. You also need to write in your first name, last name, and date of birth.Palm Beach County
The Palm Beach County ballot tracking tool requires your first name, last name, birth date, and residential zip code.
What to Do in the Event of a Ballot Tracking Issue
In the unlikely scenario that your ballot was not processed or ballot was lost, look up your local polling place and go there before 7 p.m. on Election Day. Find an elections official and explain that you checked online and discovered a problem with your mail-in ballot.An elections official will verify that your ballot was not counted and help you cast a provisional ballot.