Is what happened sufficient to clear one's conscience, or is it necessary to apologize to the girl or seek her permission?

The sound Sunnah prohibits a Muslim from proposing to a woman who has already received a proposal from his brother, in order to prevent disputes and preserve affection and harmony. Some scholars have gone further, deeming it impermissible for a woman to receive a proposal while her sister has already received one, for the same reason. If an agreement occurs between the two suitors, then repentance is obligatory, and seeking forgiveness from the fiancée, if she became aware of the matter. Otherwise, supplication and seeking forgiveness suffice. If your relative abandons proposing to the girl, he then has the option to return to her or for you to marry her.