Protection Before Sleep & Ayat al-Kursi
Explicitly established in Quran or Sahih Hadith as ruqyah/protection for this exact matter.
Allah - there is no deity except Him, the Ever-Living, the Sustainer of [all] existence. Neither drowsiness overtakes Him nor sleep. To Him belongs whatever is in the heavens and whatever is on the earth. Who is it that can intercede with Him except by His permission? He knows what is [presently] before them and what will be after them, and they encompass not a thing of His knowledge except for what He wills. His Kursi extends over the heavens and the earth, and their preservation tires Him not. And He is the Most High, the Most Great.
Say, 'He is Allah, [who is] One, Allah, the Eternal Refuge. He neither begets nor is born, Nor is there to Him any equivalent.'
Say, 'I seek refuge in the Lord of daybreak From the evil of that which He created, And from the evil of darkness when it settles, And from the evil of the blowers in knots, And from the evil of an envier when he envies.'
Say, 'I seek refuge in the Lord of mankind, The Sovereign of mankind, The God of mankind, From the evil of the retreating whisperer - Who whispers into the breasts of mankind - From among the jinn and mankind.'
How to Perform / When to Recite
Before lying down in bed, recite Ayat al-Kursi. Then cup your hands together, recite Surah Al-Ikhlas, Al-Falaq, and An-Nas, blow lightly into your palms, and wipe over your body starting from your head and face, repeating three times.
Important Safety Note: Ruqyah is a means of seeking Allah's protection and healing; it does not replace medical care. Never hang amulets or go to fortune-tellers/sorcerers.