The oxymoron "silent scream" shows the strong feelings of the author’s frustration and sadness. It puts together the loud act of screaming with being quiet, highlighting how the author wants to show deep emotions without being noticed. This choice of words creates a clear image of the inner battle, showing how strongly the author feels while looking calm on the outside.
In this context, the oxymoron stresses the author’s loneliness and their struggle to find comfort from their parents, making clear how deep their emotional pain is. It highlights the difference between what the author feels inside and what they can show on the outside.