If you look into a bright enough flashlight it could cause blindness but you would have to have a very powerful flashlight that is really, really, really bright before it blinds you.
Also you would probably not be able to handle staring at or looking into that flashlight long enough without closing your eyes before it got to the point of blinding you from looking at it.
You can get temporary blindness or partial temporary blindness if you do look into a flashlight for even a short amount of time.
I've had flashlights aimed towards my eyes before by police during traffic stops and although it made it hard to see for a few minutes I still have good eyesight.