Shall the seers be ashamed. The false prophets shall be ashamed because their oracles are proved to be delusive. They shall all cover their lips; the upper lip; i.e. the face up to the nose, in sign of mourning and shame (see Le 13:45; Ezekiel 24:17, Ezekiel 24:22).
It is equivalent to covering the head for the same reason, as Esther 6:12; Jeremiah 14:4. Septuagint, καταλαλήσουσι καὶ αὐτῶν πάντες αὐτοί, taking the verb to mean "shall open" (not "cover") their lips against them.
For there is no answer of God. There was no revelation (Psalms 74:9; Ezekiel 7:26). Septuagint, διότι οὐκ ἔσται ὁ ἐπακούων αὐτῶν, "Because there shall be none that hearkeneth unto them."