Sunan Abu Dawud
311
Hasan Sahih+3

Narrated Umm Salamah, Ummul Mu'minin: The woman having bleeding after delivery (puerperal haemorrhage) would refrain (from prayer) for forty days or forty nights; and we would anoint our faces with an aromatic herb called wars to remove dark spots

Hasan SahihAl-Albani
Hasan SahihMuhammad Muhyi Al-Din Abdul Hamid