Praise be to Allah.
The method mentioned of finding out whether a person has been afflicted with the evil eye and treating it is an innovated method (bid‘ah) and a reprehensible practice; it is not permissible to do it and it should be forbidden and warned against. It is more like witchcraft and devilish tricks than ruqyah (incantation) as prescribed in Islam or regular medical treatment.
Islam, praise be to Allah, did not omit anything that concerns people but it has discussed it and explained it clearly. But the shaytan (devil) still manages to mislead some people because of their ignorance of Islam and the ways of bid‘ah (innovation) that they are following.
Ruqyah may be done by reciting al-Fatihah, and reciting al-Fatihah as a remedy for sickness is something that has been prescribed in sharee‘ah (Islamic law), but not in this innovated fashion.
Believing that something is a means when Allah has not made it a means – either according to Islam or the laws of nature that He has decreed – is a kind of shirk (polytheism). An example of that is regarding something as a sign of healing or sickness, or of success or failure, when there is no shar‘i (legal) or physical connection between the two.
Shaykh Ibn ‘Uthaymeen (may Allah have mercy on him) said:
So long as there is no proof that a thing is a means (to an end) – either according to Islam or natural, physical laws – then it is a kind of minor shirk. That includes, for example, charms and amulets that are said to ward off the evil eye, and the like, because this is deciding that something is a means to an end when Allah has not created it to be such. Thus he is deciding about something being a means to an end, which is something that is only for Allah to decide. Hence this is like an act of shirk.
End quote from Majmoo‘ Fatawa Ibn ‘Uthaymeen.
To sum up:
The method mentioned is an innovative and reprehensible method that is more akin to the tricks of the practitioners of witchcraft and charlatans.
For information on the symptoms of affliction with the evil eye please see the answer to question no. 125543.
For more information on ways of protecting oneself from the evil eye and treating one who has been affected by it, please see the answer to question no. 20954.
And Allah knows best.