Then hung in air a moment, while He thus addressed her with a smile: “O Daksha’s child, farewell at last! For I within thy mouth have passed. Thou hast the gift of Brahmá’s grace: I go, the Maithil queen to trace.”

In plain words: Hanging in the air, Hanuman smiles and says goodbye to Surasa, daughter of Daksha. He has entered her mouth, so her gift from Brahma is fulfilled, and now he goes to find Sita.