And Balak said to Bilam: What have you done to me? I took you to curse my enemies, and behold, you have blessed them altogether.
Bamidbar Rabbah 20:19 — Balak’s protest after the first forced blessing.
English: “What have you done to me.” He said to him: I took you to curse, and you bless. Bilam said to him: Did I not tell you from the beginning — whatever Hashem puts in my mouth, that I shall speak.
Dialogue midrash reinforcing the constraint on Bilam’s speech.
Even after the first blessing, Bilam insists the words are not his — the protest of Balak is answered by the same disclaimer that opened the mission.