What should I do about the red spots that have appeared on my wife's body, and are there specific supplications (Ahadith) that can be recited, especially since one of the shaykhs said it was an evil eye?

The evil eye is real and takes effect quickly. If the one who cast the evil eye is known, he is commanded to perform ablution (ghusl), and that ablution water is used for the afflicted person. If the one who cast the evil eye is not known, then the afflicted person should seek refuge in Allah Almighty and recite the supplications for protection (ta'awwudhat) that are mentioned in the Sunnah.