This is a vintage Javanese Topeng mask--Topeng being the name for Indonesian dance is which mask-wearing, elaborately costumed performers interpret traditional narratives involving kings, heroes and myths, typically accompanied by a gamelan orchestra. I believe this mask represents the character of Prince Panji, the primary Topeng hero, identified by white face, red lips and gold painted teeth.
There are some very exquisite Topeng masks out there, but I really like the relative crudeness of this one, and especially the crooked mouth filled with a mix of gold and black teeth, which adds to its slightly sinister look. Plus the wear along the bridge of the nose, continuing the line of the right, gold-painted eyebrow.
6 7/8" tall x 5 11/16" across as measured from the back side, straight across (not on the curve. 5 1/4" from edge to tip of nose. Fits a face! On the reverse it is both strung to wear and wired to hang. 20th century. Some paint loss and wear, all to the good I think; structurally super solid and stable.