Is what happened considered a false oath (yameen ghamus)? What is the authenticity of the story of the Bedouin who uttered a false oath, and what is the verse that was revealed concerning him, and what did the Prophet, peace and blessings be upon him, advise him?

The lie you intentionally uttered, contravening the truth, and if you swore an oath upon this lie, then you intentionally swore a false oath. This is one of the gravest sins (major sins) and is called al-Yameen al-Ghamoos (the plunging oath), as stated in the Hadith (definition): "The major sins are: associating partners with Allah (Shirk (definition)), disobedience to parents (Uqooq al-Walidain), killing a soul, and al-Yameen al-Ghamoos." You must perform sincere repentance (Tawbah (definition) Nasoohah), and it is more cautious to offer an expiation for an oath (Kaffarat Yameen). Allah the Almighty has condemned swearing falsely in His Noble Book, considering it a characteristic of hypocrites and Jews.