What you can do is repent and never commit that sin again.
Whether Allah will forgive you in regards to that sin or not, whether the girl will take good deeds from you or not - you will know on Judgement Day for certain.
About oppression I found these hadiths:
[FONT="]Narrated Anas:
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[FONT="]Allah's Messenger (ﷺ) said, "Help your brother, whether he is an oppressor or he is an oppressed one. People asked, "O Allah's Messenger (ﷺ)! It is all right to help him if he is oppressed, but how should we help him if he is an oppressor?" The Prophet (ﷺ) said, "By preventing him from oppressing others." (Sahih Bukhari)
Ibn 'Abbas narrated:
"The Messenger of Allah sent Mu'adh [bin Jabal] to Yemen, and said: 'Beware of the supplication of the oppressed; for indeed there is no barrier between it and Allah.'" (Jami'at-Tirmidhi)
Narrated Abu Huraira:
Allah's Messenger (ﷺ) said, "Whoever has oppressed another person concerning his reputation or anything else, he should beg him to forgive him before the Day of Resurrection when there will be no money (to compensate for wrong deeds), but if he has good deeds, those good deeds will be taken from him according to his oppression which he has done, and if he has no good deeds, the sins of the oppressed person will be loaded on him." (Sahih Bukhari)
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[FONT="]On the authority of Abu Dharr al-Ghifari (may Allah be pleased with him) from the Prophet (ﷺ) is that among the sayings he relates from his Lord (may He be glorified) is that He said:[/FONT]
[FONT="]O My servants, I have forbidden oppression for Myself and have made it forbidden amongst you, so do not oppress one another. O My servants, all of you are astray except for those I have guided, so seek guidance of Me and I shall guide you, O My servants, all of you are hungry except for those I have fed, so seek food of Me and I shall feed you. O My servants, all of you are naked except for those I have clothed, so seek clothing of Me and I shall clothe you. O My servants, you sin by night and by day, and I forgive all sins, so seek forgiveness of Me and I shall forgive you. O My servants, you will not attain harming Me so as to harm Me, and will not attain benefitting Me so as to benefit Me. O My servants, were the first of you and the last of you, the human of you and the jinn of you to be as pious as the most pious heart of any one man of you, that would not increase My kingdom in anything. O My servants, were the first of you and the last of you, the human of you and the jinn of you to be as wicked as the most wicked heart of any one man of you, that would not decrease My kingdom in anything. O My servants, were the first of you and the last of you, the human of you and the jinn of you to rise up in one place and make a request of Me, and were I to give everyone what he requested, that would not decrease what I have, any more that a needle decreases the sea if put into it. O My servants, it is but your deeds that I reckon up for you and then recompense you for, so let him who finds good, praise Allah, and let him who finds other than that, blame no one but himself. It was related by Muslim (also by at-Tirmidhi and Ibn Majah).[/FONT]
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Some Duas seeking forgiveness
[FONT="]Narrated Shaddad bin 'Aus:
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[FONT="]The Prophet (ﷺ) said, "The most superior way of asking for forgiveness from Allah is: 'Allahumma anta Rabbi la ilaha illa anta. Khalaqtani wa ana `Abduka, wa ana 'ala 'ahdika wa Wa'dika mastata'tu abu'u Laka bi ni 'matika wa abu'u Laka bidhanbi; faghfirli fa'innahu la yaghfiru-dh-dhunuba ill a ant a. A'uidhu bika min sharri ma sana'tu.' If somebody recites this invocation during the night, and if he should die then, he will go to Paradise (or he will be from the people of Paradise). And if he recites it in the morning, and if he should die on the same day, he will have the same fate." (sahih Bukhari)
`Abdullah bin `Amr narrated from Abu Bakr As-Siddiq that he said:
“O Messenger of Allah, teach me a supplication that I may supplicate with in my Salat.” He (ﷺ) said: “Say: ‘O Allah, I have wronged myself much, and none forgives sins except You. So forgive me with forgiveness from You, and have mercy upon me, indeed, You are the Forgiving, the Merciful (Allāhumma innī ẓalamtu nafsī ẓulman kathīran wa lā yaghfirudh-dhunūba illā anta faghfirlī maghfiratan min `indika warḥamnī innaka antal-Ghafūrur-Raḥīm).’” (Jami'at Tirmidhi)
7:23 R[FONT="]abbana thalamnaanfusana wa-in lam taghfir lana watarhamnalanakoonanna mina alkhasireen[/FONT]
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