There are some people who place their right hand on their forehead and say some dua right after the fardh prayer.
It has been narrated Anas ibn Malik with the chain as follows:
حَدَّثَنَا أَبُو مُسْلِمٍ الْكَشِّيُّ، ثنا حَفْصُ بْنُ عُمَرَ الْحَوْضِيُّ، ثنا سَلَّامٌ الطَّوِيلُ، عَنْ زَيْدٍ الْعَمِّيِّ، عَنْ مُعَاوِيَةَ بْنِ قُرَّةَ،
كان رسول الله ﷺ إذا قضى صلاته مسح جبهته بيده اليمنى، ثم قال: أشهد أن لا إلى إلا الله الرحمن الرحيم، اللهم أذهب عني الحزن
When Prophet ﷺ finishes his prayer, he would touch his forehead with his right hand and say: " I bear witness that no God but Allah he is the most merciful and compassionate. O Allah! remove the sadness and afflictions from me".
[Amal al Yaum wal Laylah by Ibn Sunni #112, Kitab ad Dua by Imam Tabarani #659, Nata'ij al Afkar by Ibn Hajar 2/301, Hilyatul Awliya 2/301-302]
This narration is extremely weak - Salam at Taweel is Matrook [al Taqreeb 2706]
Imam Bukhari رحمہ اللہ said "تركوه" [Kitab al Zuafa pg. 51, #155]
Imam Hakim Nishapuri said: He narrated fabricated hadith from Hameed at Taweel, Abu Amr ibn Ala and Thawr ibn Yazeed. [al Madkhal pg. 144]
Hafiz Haythami said: "وقد اجمعوا على ضعفه" [Majma al Zawaid pg. 1/212]
Imam ibn Hajar said: "والحديث ضعيف جدابسببه" [Nata'ij al Afkar 2/301]
Second narrator Zaid al Ami is weak [Taqreeb at Tahzeeb #2131]
Majority of Mohaddiseen declared him weak [Majma Zawaid 10/110]
Hafiz Haythami writes:
وبقية رجال أحد إسنادي الطبراني ثقات وفي بعضهم خلاف
And rest of the narrators are trustworthy from one of the two chains of transmission from Imam Tabarani and has dispute in some.
[Majma Zawaid 10/110]
Shaikh Zubair Ali Zai رحمہ اللہ said: Second narration of Imam Tabarani is no where found however, Hafiz Haythami might be indicating this narration from Imam Bazzar
حدثنا الحارث بن الخضر العطار : ثنا عثمان ب ن فرقد عن زيد العمي عن معاوية بن قرة عن أنس بن مالك رضي الله تعالىٰ عنه
[Kashf al Astar 4/22]
Nothing found regarding Khizr al Attar, and it is more likely possible that he dropped the "Salam at Taweel" from the transmission of Usman bin Farqad and Zaid al Ami. if he didn't drop the transmission even then the narration is rejected because Khizr al Attar is Majhool (Unknown).
It is transmitted from the chain of Kathir bin Sulaym - Anas ibn Malik
كان رسول الله صلى الله عليه وسلم صلى الله تعالىٰ عليه وسلم إذا قضي صلاته مسح جبهته بيمينه ثم يقول : باسم الله الذى لا إله غيره، اللهم اذهب عني الهم و الحزن، ثلاثاً
When Prophet ﷺ would finish his prayer, he touches his forehead with his right hand and recite "In the name of Allah, there's no God but him, O Allah! remove the sorrow and afflictions from me"
[al Kamil by Ibn Adi 7/199, Kitab ad Dua by Imam Tabarani #658, al Amaali by Shajri 1/249, Tarikh Baghdad 12/489, Nataij al Afkar 2/301-302]
Kathir bin Sulaym is declared Munkireen Hadith By Imam Bukhari [Kitab Zuafa 316]
It is not permissible to transmit from a narrator who's declared Munkireen Hadith by Imam Bukhari [Lisaan al Mizan 1/20]
Imam Nasai رحمہ اللہ declated Kathir bin Sulaym "متروك الحديث" [Kitab Zuafa al Matrokeen 506]
Matrook narrator's narration is also not reliable in Shawahid and Mutabiyat [ref: Ikhtesar Uloom Hadith By Ibn Kathir pg. 38]
Imam Albani رحمہ اللہ also declared him "ضعيف جداً" [Silsilatus Zaeefa #660]
Imam Suyuti also declared him weak [al Jami Sageer #6741]
Mohammad Arshad Qasmi Deobandhi also declared him weak mentioning "al Jami Sageer and Majma Zawaid".
Mufti Tariq Masood also consider these narrations weak which talks about placing hand on forehead after Salah.
Shaikh Zubair Ali Zai رحمہ اللہ said: Nothing is proven from the Sunnah of Nabi ﷺ that he placed his hand on forehead and uttered dua hence, people should refrain from acting upon such things.
