If MySQL backups have been configured within WHM > Backup > Backup Configuration, then the server may have a recent backup already. First, check to see where backups are being stored and what kind of MySQL backups are being taken:
grep 'BACKUPDIR\|MYSQL' /var/cpanel/backups/config
BACKUPDIR is where cPanel will store the backups if they are being retained locally. While having these backups are useful, it may be prudent to generate a more current backup of MySQL.
MYSQLBACKUP can return any of the following:
accounts- all databases under each cPanel account are backed up directly into the account's backup
dir- the MySQL data directory is backed up only (custom data directories are taken into account)
- both - each cPanel account will have their databases backed up directly into their backup, and the MySQL data directory is backed up separately