Sekhmet was the mother of Nefertem in Memphis. Dyads show both deities standing or seated and are of the New Kingdom onwards (see below).1 However, most are of the Late Dynastic Period

Blue serpentine dyad of Sekhmet and Nefertem

Blue serpentine
H 6.8, W 5.1, T 1.1 New Kingdom
© 2011 Musée du Louvre/Antiquités égyptiennes #E 24276

Faded green glazed plaque of Sekhmet and Nefertem
Back of the faded green glazed plaque of Sekhmet and Nefertem

Faded green glazed plaque flatback, broken at base H 5.2, W 2.8 Undated
© 2021 Musée du Louvre/Antiquités égyptiennes #N 3863

Reference

1Andrews C. Amulets of Ancient Egypt, 1994, pp. 18-19 and Fig. 13d