What should I do in order to protect myself from the possession of Jinn?

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, sallallaahu ‘alayhi wa sallam, is His slave and messenger.

In a Hadeeth on the authority of Abu Hurayrah the Prophet instructed he who sees an afflicted person to thank Allaah Who spared him from that affliction. [ At-Tirmithi]

A Muslim should avoid going to places where he could see patients who are possessed by Jinn or epileptics like the places where they receive treatment. Let him thank Allaah for the blessing of wellness. A Muslim should protect himself by means of saying the Athkaar (supplications and the legislated mention of Allaah) and maintaining a state of purity (by performing ablution) as much as possible. He should recite the chapters of Al-'Ikhlaas, Al-Falaq and An-Naas (chapters 112, 113 and 114 of the Quran), while supplicating Allaah much to protect him.

Dear Brother, you have to know that nothing can harm or benefit you except with the permission of Allaah. Allaah Says (what means): {And if Allaah should touch you with adversity, there is no remover of it except Him. And if He touches you with good - then He is over all things competent.} [Quran 6:17]  We implore Allaah to grant you and us safety and wellness.

Allaah Knows best.