Whenever the Prophet ﷺ sneezed, he would cover his face with his hand or with his garment and lower his voice with it.
حدثنا محمد بن وزير الواسطي حدثنا يحيى بن سعيد عن محمد بن عجلان عن سمي عن أبي صالح
أن النبي ﷺ كان إذا عطس غطى وجهه بيده أو بثوبه وغض بها صوته
No references are available.
[Its chain is hasan] Abu Dawud also narrated it in the Book of Manners, chapter on sneezing, no. 5029, from the hadith of Yahya Qattan with the same wording. Ibn Ajlan explicitly stated that he heard it directly, as recorded by Ahmad: 2/439, and Hakim graded it sahih: 4/293, and Dhahabi concurred with him.