The phrase "silent scream" is a powerful oxymoron that effectively captures the author's frustration and sadness. By combining the idea of a loud scream with silence, it conveys the author's desire to express intense emotions that go unnoticed. This juxtaposition creates a vivid picture of an internal struggle, emphasizing the depth of the author's feelings, even when they appear composed on the surface.
In this context, the oxymoron also underscores the author's sense of loneliness and their difficulty in seeking comfort from their parents. It illustrates the significant contrast between their inner emotional turmoil and the calm facade they maintain outwardly.