With the energy of the Sound Transmission Amulet already slightly altered by He Song, True Monarch Youyun wouldn't possibly notice anything amiss.
Thus, in this exchange of telepathic talisman energy with True Monarch Youyun, there naturally wouldn't be any oversights on He Song's part.
True Monarch Youyun would only believe that he had made the acquaintance of a Golden Elixir Master.
And he would not discover that this Unknown Golden Elixir in his eyes, was actually He Song, who he had had a fleeting encounter with before.
In such cases, He Song naturally also had no need to worry about his identity being exposed anymore.
As for what followed.
Whether He Song would keep this newly purchased telepathic talisman with him at all times depended on his own choice.
Choosing to keep this newly purchased telepathic talisman by his side, he could naturally continue to contact True Monarch Youyun in the guise of True Monarch Feiyu.