(28) Events of the Day of Resurrection and the Beginning of Creation
كتاب أحوال القيامة وبدء الخلق
(7b) Chapter: Description of Hell and its Inhabitants - Section 2
(7) باب صفة النار وأهلها - الفصل الثاني
Mishkat al-Masabih 5684 
Abu Sa'id reported the Prophet as saying regarding "And they in it will be showing their teeth[*]," that the fire will roast a person and his upper lip will retract till it reaches the middle of his head, and his lower lip will hang down till it strikes his navel." *Quran; 23:104 Tirmidhi transmitted it.
وَعَنْ أَبِي سَعِيدٍ عَنِ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ قَالَ: (وهم فِيهَا كَالِحُونَ) قَالَ: «تَشْوِيهِ النَّارُ فَتَقَلَّصُ شَفَتُهُ الْعُلْيَا حَتَّى تَبْلُغَ وَسْطَ رَأْسِهِ وَتَسْتَرْخِي شَفَتُهُ السُّفْلَى حَتَّى تضرب سُرَّتَهُ» . رَوَاهُ التِّرْمِذِيّ
Reference : Mishkat al-Masabih 5684
In-book reference : Book 28, Hadith 155