What should I do if I mistakenly washed a limb before another during wudu, and I had already finished my prayer, and I only became certain of the mistake the following day?

Observing the order in ablution (wudu') is obligatory, and the proof for this is Allah's Almighty saying: ﴿O you who have believed, when you rise to [perform] prayer, wash your faces and your forearms to the elbows and wipe over your heads and wash your feet to the ankles﴾. If a Muslim intentionally deviates from this order, their ablution is invalid, and they must repeat it. However, if it was due to error or forgetfulness, the correct view is that they are not required to repeat it, but it is recommended to repeat the prayer as a precaution. The order between the right and left in washing the hands and feet is not obligatory, nor is the order between rinsing the mouth (madmadah) and sniffing water into the nose (istinshaq) with washing the face.