Is the female student considered a wrongdoer, and what is the expiation for her action, and what is the expiation for her false oath, for lying and fabricating an accusation of assault against her neighbors who had previously wronged her and caused injury to her mother?

Lying is one of the major sins, and the injustice of an oppressor does not make it permissible. However, if you lied to obtain a pre-existing right that you could not achieve except through lying, then there is no harm in it, and swearing an oath in this case is permissible.

But if you had no right, or if you had already obtained it, then lying is not permissible, and if you did so, repentance is obligatory. Your oath at that time would be considered an oath that plunges one into sin (yamin ghamoos), which is one of the greatest major sins that immerses its perpetrator in the Fire. The majority of scholars hold that its expiation is repentance, while Al-Shafi'i stated that expiation is obligatory along with repentance.

Repentance for lying related to the rights of others necessitates seeking absolution and returning any money you took, or seeking forgiveness from those who were harmed by your lie. It is also necessary to be patient with the harm from relatives and treat them with kindness.