Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
quran:23:104

The Fire will sear their faces, and they therein will have taut smiles.  

The Fire will scorch their faces, it will burn them, while they glower therein, their upper and lower lips having receded from their teeth, and it will be said to them:
القرآن:٢٣:١٠٤

تَلْفَحُ وُجُوهَهُمُ النَّارُ وَهُمْ فِيهَا كَالِحُونَ  

{تلفح وجوههم النار} تحرقها {وهم فيها كالحون} شمرت شفاههم العليا والسفلى عن أسنانهم، ويقال لهم.