A hard face is a metaphor for being stubborn. Alternate translation: "I have made you as stubborn as they are" (See: [[rc://en/ta/man/translate/figs-metaphor]])
The "brow" is the forehead or eyebrow and is a metonym for what the person thinks. Alternate translation: "I have made ... you strong so you will not stop doing what you are doing" (See: [[rc://en/ta/man/translate/figs-metonymy]])