Dr. Marawan Shahin, Professor of Hadith and its Sciences, Faculty of Usul Ad-Din (Theology),Al-Azhar Univ. states: “Experiencing a wet dream in the state of ihram does not affect ihram or the validity of Hajj. However, in this case one is recommended to perform ghusl (purificatory bath) as soon as he can in order to be eligible and pure to perform acts of worship. May Allah reward you and accept your Hajj!
Allah Almighty knows best.