For now, i will just wait more answer, maybe you can restore everthing so wait.
About the backup, you have this on the panel admin, (upload and restore option)
I guess if you have a backup (and you can’t access to your current admin panel) you can setup fresh install then upload and restore the backup. 
Edit
don’t forget to allow backup on /admin/site_settings/category/backups thx to @cpradio