RDS infinite reboot loop after parameter group changes

I recently changed about 5 parameter group variables on my MariaDB RDS instance and changed the parameter group to my new custom one. This apparently required a reboot, which I did. It has now been an hour and the database is stuck in the "Rebooting" status. About every 3-4 minutes a new "DB instance shutdown" event is created. The logs don't show anything except the first reboot after applying the new parameter group about 45 minutes ago.

So the question is, did I brick this database from a bad custom param? Is there any way to stop the reboot process so I can revert the param group change back to default? I've started to create a new DB based on the most recent snapshot but I'd rather not lose ~8 hours of DB changes if I don't have to.

Thanks!