First of all scary lung means fibrosis
of lungs and if its on the top of the lungs then most probably TB will be the cause , in many people with good immunity usaually TB is treated on your own with no medicine and after winning from TB your lung becomes scared.
You can proceed to any country till you get a montoux , ESR
, sputum test for Tb mycodot , attach the tests and you can show them you had old TB and you cant spread it.And you can easily go to any country
There are other causes of scarring like AS , Rheumatoid , Asbestosis
, fungal infection
and so on.
Get a clean chit from pulmonologist and enjoy this world.
Hope this helps