And in RedHat/CentOS based systems it should be at /var/named.you can edit the DNS entries in your BIND directory using Terminal SSH.
in Debian it's /etc/bind/
And any time you edit a zone file you should increment the serial number before restarting BIND, to make sure any slave systems you have in place will get the new information.and you just edit the appropriate zone file: eg: domain.com.db
I'd suggest looking at another zone file to check if it's all intact.
If you do edit any of this, be sure you restart or reload your bind service.