Praise be to Allah.

Firstly:  

Curing a person who have been bewitched or had a spell cast on him, if it done by permissible means, comes under the heading of the treatment of sickness and disease. It is one of the best of deeds if one seeks the pleasure of Allaah thereby, especially if that is also for the purpose of solving marital or family problems. 

There are two scenarios that may apply in curing one who has been bewitched: 

1 – Lifting the spell by means of further witchcraft, where the practitioner of witchcraft and the sick person seek to draw close to the jinns and devils in order to cure the spell. This is haraam and it is a great evil and the work of the Shaytaan, as it says in Musnad Ahmad (3/294) and Sunan Abi Dawood (3868), where it is narrated that Jaabir ibn ‘Abd-Allaah (may Allaah be pleased with him) said: The Messenger of Allaah (peace and blessings of Allaah be upon him) was asked about nushrah, and he said, “It is the work of the Shaytaan.” Classed as saheeh by al-Albaani in Saheeh Abi Dawood, 3868. 

Nushrah means curing a person who has been bewitched. What is referred to here is the type of nushrah that was used during the Jaahiliyyah, which is curing witchcraft by means of witchcraft or by using the services of the devils. 

See al-Qawl al-Mufeed ‘ala Kitaab al-Tawheed, by Shaykh Ibn ‘Uthaymeen (may Allaah have mercy on him). 

The way in which this hadeeth indicates that it is haraam is that the Prophet (peace and blessings of Allaah be upon him) described it as being the work of the Shaytaan, and whatever is the work of the Shaytaan is haraam, for the Shaytaan enjoins evil, immorality and saying of Allaah what one does not know. 

2 – Lifting the spell by means of the ruqyahs and prayers for refuge with Allaah that are prescribed in Islam, and using permissible kinds of medicine. This is permissible and is a righteous deed for which a person will be rewarded, so long as he observes the proper etiquette of treatment and performing ruqyah. See question no. 12918. 

Secondly: 

Our advice to the who uses witchcraft to fight witchcraft is to fear Allaah and to hasten to repent from this action which poses a threat to his religious commitment and his Islam, before the Angel of Death comes down to him and catches him unawares, whereupon regret will be to no avail and there will be no turning back. The danger that witchcraft poses to one's religious commitment is very real and very serious. Allaah has told us in His Book that learning and teaching witchcraft is kufr as He says (interpretation of the meaning): 

“They followed what the Shayaateen (devils) gave out (falsely of the magic) in the lifetime of Sulaymaan (Solomon). Sulaymaan did not disbelieve, but the Shayaateen (devils) disbelieved, teaching men magic and such things that came down at Babylon to the two angels, Haaroot and Maaroot, but neither of these two (angels) taught anyone (such things) till they had said, ‘We are for trial, so disbelieve not (by learning this magic from us).’”

[al-Baqarah 2:102]

So learning and teaching witchcraft constitutes kufr or disbelief in Allaah. In al-Saheehayn it is narrated from Abu Hurayrah (may Allaah be pleased with him) that the Prophet (peace and blessings of Allaah be upon him) said: “Avoid the seven (sins) that doom a person to Hell.” They said: “O Messenger of Allaah, what are they?” He said: “Associating others with Allaah (shirk), witchcraft, killing a soul whom Allaah has forbidden killing, except in cases required by law, consuming riba, consuming the orphan’s wealth, running away from the battlefield, and slandering chaste and innocent believing women.”  

These are all sins which will doom a person to Hell, so let this practitioner of witchcraft beware of the wrath and punishment of Allaah, for His punishment is painful and severe. Let him beware of the traps of the Shaytaan who makes this deed appear attractive and makes him think that it is in the interests of the Muslims and a solution to their problems, until he drags him to Hell and causes him to be thrown therein, what a terrible end. Beware, for the matter is very serious, it is the matter of eternal bliss or eternal misery; we seek refuge with Allaah from loss and utter misery. 

Thirdly: 

Our advice to the sick person who has been bewitched is to be patient and seek reward from Allaah. He should realize that this is a test through which he may raise his status before Allaah if he is patient and seeks reward. Al-Tirmidhi (2396) and Ibn Maajah (4031) narrated from Anas ibn Maalik (may Allaah be pleased with him) that the Prophet (peace and blessings of Allaah be upon him) said: “The greatest reward comes with the greatest trial. When Allaah loves a people He tests them. Whoever accepts that wins His pleasure but whoever is discontent with that earns His wrath.” Classed as hasan by al-Albaani in Saheeh al-Tirmidhi, 2396. 

He should depend on Allaah alone and put his trust in Him in all his affairs, as well as following the means prescribed in sharee’ah and the permissible practical means of treating his disease. He should turn to Allaah and beseech Him with du’aa’ at the end of the night, and following each prayer, for Allaah is the One who removes harm and relieves distress. He is merciful to His believing slaves and answers the du’aa’ of the one who is in difficulty. 

“Is not He (better than your gods) Who responds to the distressed one, when he calls on Him, and Who removes the evil, and makes you inheritors of the earth, generations after generations? Is there any ilaah (god) with Allaah? Little is that you remember!”

[al-Naml 27:62]

Let him beware of approaching the ways of witchcraft, soothsaying and fortunetelling, for they are a disease and a malady which lead to certain doom. In Saheeh Muslim (2230) it is narrated from one of the wives of the Prophet (peace and blessings of Allaah be upon him) that the Prophet (peace and blessings of Allaah be upon him) said: “Whoever goes to a fortune teller and asks him about anything, his prayers will not accepted for forty days.” In Musnad al-Imam Ahmad (9252) it is narrated from Abu Hurayrah and al-Hasan (may Allaah be pleased with them) that the Prophet (peace and blessings of Allaah be upon him) said: “Whoever goes to a soothsayer or a fortune teller and believes what he says has disbelieved in that which was revealed to Muhammad.” Classed as saheeh by Shaykh al-Albaani in Saheeh al-Jaami’, 5939. So let the Muslim beware of asking them about anything or believing them, in obedience to Allaah and His Messenger (peace and blessings of Allaah be upon him), and so as to protect his religious commitment and his belief (‘aqeedah), and out of fear of the punishment of Allaah, and so as to avoid the things that lead to shirk and kufr, for whoever dies in a state of shirk or kufr will have lost in this world and in the Hereafter, and that is true loss.