This mask of a scarified woman with lip plug was made and used by the Makonde of Tanzania. This mask is a rarer face mask than the similar helmet masks as it is worn over the face with holes for the eyes.  Face masks, unlike helmet masks, are worn by stilt dancers. It is used primarily for the mapiko dance held at adult initiation rituals for boys and girls. The masquerader channels the spirit of dead ancestors through the mask.   During initiation, boys and girls are both taught how to make the masks and perform them.  Women perform their initiation away from the males, who never see the masquerade.
(from Second Face - The Museum of Cultural Masks USA)

The Makonde are a matrilineal society. They adhere to an ancestrally based spirituality. Their matrilineal social structure, meaning ancestry is traced through the female line, is rooted in their creation story, which speaks of the first man who sculpted a woman out of wood. This woman became real and gave birth to the first man’s many children and as a result became the venerated ancestress of the Makonde people (Tribal African Art). Because of this, the female figure is an important protective symbol in Makonde society and in their art, as seen in the body mask (a body mask of a pregnant belly and breasts). 
Once the mask, along with the rest of the full-body costume and accessories including beads, rattles, kerchiefs, flywhisks, and scepters are in place, the dancers take on the role of whatever character their costume represents. The individual’s human status is no longer recognized as he participates in the foundational myth that allows him to fully embody the spirit and character of the mask. This spirit is so powerful that the men can hardly control it and the women cannot go near it.
(Savannah Phelan, Pacific Lutheran University)

Here we have a very powerful female face with grooved cheeks to imitate scarification and an upper lip plug, these were not generally worn after the 1930s so this could be quite an old mask or an ancestor. It is carved out of a lightweight wood and has some of the rim at the upper back missing. But this does not affect the view of the mask from the front.
 Supplied without stand, it works perfectly hung on the wall.
Height 9ins/ 23 cms
Guaranteed tribally used
Ex collection Bryan Reeves

Makonde mask of female ancestor with lip plug, Tanzania. African tribal mask