I never have TB Problem why my Lungs have scars?

However the reason for Fibrosis lungs may TB infection currently or in the past cured Tb which leaves scars on lungs. The answer to the question is immune system.  For Example You are living in a situation where the Tb germ is present or your friend, family, colleague or any other person you interact with have suffering from Tuberculosis which in infectious disease which means that the TB germ passes from one effected person to one or more normal person .

You interact with him and through the air germ moves from his/her body to your body, immediately the immune system of your body will active and fight against that germ if the immune system of your body is powerful enough (based on balanced diet) to fight it will deactivate the TB germ and may make scars depending upon the intensity of germ and no symptoms of TB will occur to you even you will unaware of this.

Contrary to it, if the TB germ which enters to your body is more powerful than your immune system your body will show the symptoms of TB you will consult the Pulmonologist and he will give you medicine to fight against germ/virus such treatment may cause scar or not depending upon the stage.