It's a condition where a person can't distinguish faces !

It can be a congenital or acquired condition.

When a person injures his head on the back (occiput region) or near to the back of the ear ,he might get an injury on a structure called fusiform gyrus.(The human brain has sulci and gyrl.Sulci are the depressions of the brain and Gyri are the upward projections)

This  gyrus is responsible for perception (not just seeing but more of observation).This special function is required to distinguish faces, be it an animal's or human's face .

If the injury is severe ,the  person can have complete prosopagnosia (can't distinguish human and animal faces .Both of them appear very blurry),in mild injury person might be able to distinguish animals (still in the research process , no proper conclusion can be made as of now )

In a textbook of medicine,I had read about it having some relation with special connections.If the person has a very close ,loved one he could be able to distinguish them even without using other senses like smell ,voice etc .

This disease is a very rare one ,hence it has no exact :some see only eyes and rest blurred ,some see whole face blurry (just like the male protagonist in this series  ) Injuries to head commonly affects nerves , mostly the facial nerve -leads to complete paralysis of face ,the person can't make facial expressions)

Prosopagnosia has no specific treatment yet ... unfortunately!

Hope this helped you guys !

I thought this condition was fictitious. Only exiting in dramas. Thanks for making that clear!

Welcome dear !Glad it helped!