With faces and clothing spotted with plaster and papier-mâché, students in “The Art of the Mask” workshop can’t say they weren’t warned. The final sentence in the brochure description for the workshop at the Averitt Center for the Arts reads, “Please wear cloths suitable for getting messy.” Under the instruction of Scott Fox, a long time puppeteer and mask maker, the class focuses on the art and history of the mask, ranging from Commedia dell’arte to New Orleans styles.