The phrase 'forever influenced' is correct and can be used in written English.
You can use it when you are referring to something or someone that has been permanently affected. For example, "The teachings of the great philosopher will forever influence the way we think."
We will be forever influenced by his vision.
His pioneering work as an Abstract-Expressionist sculptor forever influenced the landscape of art history.
In 1926 the Société mounted the International Exhibition of Modern Art at the Brooklyn Museum, an exhibition that forever influenced the way people would view modern art.
The work of all who dared dream of a world of dignity was and will be forever influenced by him.
These include the late Julius Schulman talking about the growth of Los Angeles, complete with all his much-missed boosterish egocentrism and Frank Gehry explaining how being part of L.A.'s art scene with Wallace Berman, among others, forever influenced his work, and how his childhood study of Talmud sparked his disputatious spirit.
The culture at Uber is one that I would like to put behind me, but not forget as it will forever influence the professional and personal decisions I make on a daily basis".
Art that lives forever, influences future art.
To embark on a course that will forever influence their futures.
Ali, who died Friday, leaves behind a legacy that will forever influence those who admired him, especially young black boys who look to Ali as a hero and an example of black excellence and achievement in America.
Author Dan Charnas -- whose cred comes partly from his years of working with Rick Rubin -- traces the genre's rich history from rap's street battles through MTV Raps and hip-hop's eventual conquering of the singles charts, forever influencing rockers and popsters along the way.
She could forever be influenced in how she acts or what she says for fear he might batter her again.
