Praise be to Allah,
People who have had experience with such situations have related that the following are among the signs of a person who is possessed by jinn (or Satan):
Strong repulsion when hearing Qur’an or Adhan (call for prayers).
Episodes of losing consciousness and/or epileptic attacks, especially when Qur’an is recited for the possessed person.
Frequent nightmares during sleep.
Tendency to avoid people accompanied by out-of-the-norm behavior.
The jinn who possesses him might speak when Qur’an is recited for the possessed person.
Madness, as stated in the Qur’an (interpretation of the meaning): “Those who devour usury will not stand except as stands one whom Satan by his touch hath driven to [epileptic] madness…”2:275
Shaykh Muhammad Ibn Saleh al-‘Uthaymīn—رحمه الله—said:
“ينبغي على الإنسان أن يستعين بالله عز وجل في كل شيء حتى في الأمور الصغيرة : كالذهاب والمجيء والأكل والشرب واللباس. حتى يكون بذلك مدركاً لحاجته متعبدا لربه عز وجل لأن الاستعانة من العبادة وإذا استعان العبد بربه يسر له الأمر وسهله عليه.”
“It’s befitting for man to seek assistance with Allāh—عز وجل—in everything—even in the small matters like leaving to and from [somewhere], eating, drinking and dressing—so that with this, he can fulfill his need AND worship his lord—عز وحل. Because al-Isti’ānah (seeking assistance) is from the acts of worship and if the slave seeks assistance from his lord, He (Allāh) will facilitate the matter for him and make it easy.”
Ahkām Min al-Qur’ān al-Karīm, 1/3
As for a person struck by magic, he might experience the following:
Dislike of one’s spouse, as indicated in the Qur’an by the following verse (interpretation of the meaning): “And from these (angels) people learn that by which they cause separation between a man and his wife…” (Al-Baqarah, 2:102).
Different attitude in the house from that which is outside the house. For example, a person will feel that he is missing his family when is outside the house but when he goes home, love changes quickly to extreme hatred.
Inability to have sexual intercourse with one’s spouse.
Frequent miscarriage for pregnant women.
Sudden change in behavior without obvious reason.
Complete loss of appetite for food.
Thinking or imagining one has done something when in reality one has not.
Sudden obedience and/or love for a particular person.
It should be noted that if a person experiences some of the above symptoms this does not necessarily mean that he is either possessed by a jinn or struck by black magic. It might be due to physiological or psychological reasons.
As for curing this condition, the following steps are recommended:
Putting one’s trust in Allah with the sincere belief that He is the only cure for everything.
Reading Qur’an and known supplications expressing seeking refuge, the most important and effective of which is surah 113 and 114, Al-Falaq and Al-Naas, which were used to cure the Prophet himself. Surah 112, Al-Ikhlas, is recommended along with them, as well as the opening chapter of the Qur’an, Al-Fatihah. To cure black magic some have successfully used seven lotus-tree leaves. The leaves should be crushed, then mixed them with water enough for taking a bath. The following verses from the Qur’aan are then recited: verse Al-Kursi (2:255), surah Al-Kafiroon (109), surah 112, 113, 114; the verses which mention magic, which are: in surah Al-Baqarah (2:102), Al-A’raf (7:117-119), Yunus (10:79-82), and Taha (20:65-69). The possessed person drinks some of the water, and the rest is used to give him a bath.
Removing the elements of magic as was done by the Prophet SAW when he was struck by black magic by a Jewish man called Lubaid Bin Al-‘Aasim.
Eating seven Aa’liya Al-Barniy dates (among the dates of Al-Madinah) first thing in the morning; if not possible, any dates will suffice, by the will of Allah.
Cupping – removing excess blood.
And we ask Allah to cure you and ease your hardship, as He is the One who cures and there is no one else who can cure. Ameen