Repair help needed urgently!!!

This part has come unattached from the fine tuner peg! I have a recital tomorrow and would rather not use a loaner cello. Is there any way that I can fix this myself? Any help appreciated.

This part has come unattached from the fine tuner peg! I have a recital tomorrow and would rather not use a loaner cello. Is there any way that I can fix this myself? Any help appreciated.