Is it permanent if somebody has sudden hearing loss followed by ringing in ears?

Seek treatment soon. Sudden sensorineural hearing loss is a medical emergency that is best evaluated by an ENT physician, and which may respond to treatment. Other types of hearing loss and ringing, such as fluid or wax in the ear, are less urgent but almost always correctable. For more information, see the ENT academy guidelines at http://www.Entnet.Org/community/shlguideline.Cfm.
Get seen immediately. Sudden hearing loss is an ominous sign. I would call an ENT (ear nose and throat specialist) immediately for advise or get your pcp to make an urgent referral.