If I recreate the DB tables will I lose all my existing log entries? Is there a way to see the database changes?
I recommend using an external database, it is much better in every way, you can even use a free external database.
But in your case, stop the visualcronservice, go to C:\ProgramData\VisualCron\output\log\VisualCron4.sdf (default path) and rename the sdf file toa tmp file and it will create a new database file and you can see if the health log is there.