Legal Question in Civil Litigation in Tennessee

You posted your question under General Civil Litigation, but double jeopardy applies only in criminal cases. You also refer to the pro se party as a "litigant", which is a term normally reserved for civil cases. It is not possible for a civil case to put the defendant in double jeopardy.

Perhaps this really was a criminal case and you just posted in the wrong category. If so, the defendant should bring whatever sort of challenge is available in the trial court and should also take the case to the state court of appeal. There is no way to ask a federal court to review a state trial court criminal judgment unless the defendant first exhausts his state-court remedies. He can then petition the U.S. Supreme Court to take his case and/or can petition the U.S. District Court for a writ of habeas corpus.

Note that habeas corpus is only available in criminal cases. If this is a civil case, then the habeas option is not available.

Finally, you shouldn't be concerned that the state appeals court will favor the state because it doesn't want to subject the state to civil liability. Such cases come up reasonably often, and virtually all state court appellate judges are able to handle them fairly.