To what extent is the veiled girl's decision to wear the niqab after performing Istikhara valid? And is her psychological struggle and wavering in adhering to it a result of the Istikhara or of waswasah (whisperings)? And how can she deal with herself and her moody personality to achieve steadfastness, especially with no role models or veiled friends around her?

There is no place for Istikhara concerning covering the face. One should not pay attention to the whispers of Satan, but rather remain steadfast in obedience and seek Allah's help. It is also important to benefit from the lessons and admonitions of scholars and to associate with righteous women. If the complete hijab causes significant hardship or difficulty, this is not a justification for abandoning it entirely, because what is achievable is not forfeited due to what is difficult. One must strive against the self and oppose desires, seeking Allah's pleasure.