Hermod spotted her when she walked in. Even if the mask hadn’t shown who she was, he liked to think that would still know her. He knew Bast’s body well enough that he did not think she could hide from him for long.
He was fairly certain she noticed him. She might not realize that it was him under the rabbit mask. That was fine. He knew she would come to him before the night was over. He would just stand there and wait for her. At least for now.