Wiktionary
blacked up
vb. (en-pastblack up)
Usage examples of "blacked up".
One ear was sot back on his neck, 'n' his tail was stove up, 'n' his eye-winkers was swinged off, 'n' he was all blacked up with powder an' smoke, an' all sloppy with mud 'n' slush f'm one end to the other.
Although the way she blacked up as a Negro boy and involved Doc in the thing shows she isn't adverse to a little adventure herself.