All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
Usually, a bewitched person suffers from the symptoms of the spell that is cast upon him. For example, he may become unable to have intimate relations with his wife, or imagine certain things that did not take place, or become forgetful. The proof for this is that the Prophet, sallallaahu ‘alayhi wa sallam , displayed these symptoms of a spell when it was cast upon him. It was narrated on the authority of ‘Aa’ishah that when a spell was cast upon the Prophet, sallallaahu ‘alayhi wa sallam, he would imagine having done certain things that he had not done. [Al-Bukhari and Muslim]
The wording of another narration reads that he would imagine that he had intimate relations with his wives when he had not. Sufyaan said that this is the severest type of magic.
Other symptoms may not be perceived by others, such as having nightmares. However, it should be noted that both kinds of symptoms may not be due to magic spells; many people who are not bewitched may have similar symptoms.
Allaah Knows best.