For all wh-questions, eyebrows are furrowed along with intonation.
Often, fluent and native Deaf signers omit the "what" part. The inflections of the single "what"-omitted sign can convey a few different meanings that we can understand with the senstivity to subtleties of intonation, including facial expression and subtle movements. E.g. "What's the matter?", "nothing wrong with that", and a few others.