Dreams involving feelings of confinement, such as being in a glass box, can often symbolize feelings of entrapment or lack of control in your waking life. The blackness surrounding the box may represent feelings of despair or anxiety, and the whispering voices could signify inner thoughts or external pressures that are difficult to confront.

The act of seeing yourself in a white dress might symbolize innocence or purity, contrasting with the distressing imagery of hair on the floor and the bald patch on your head. This could indicate a struggle with self-image or the consequences of your trichotillomania, reflecting a fear of how this behavior is impacting your sense of self.

The words "Haha" could suggest feelings of mockery or self-criticism, which might be tied to your feelings about your condition. The fleeting nature of the words fading into black might symbolize the temporary relief you may feel after pulling your hair, followed by a return to distress.

Overall, this dream could be your subconscious mind processing your struggles, fears, and feelings of isolation related to trichotillomania. Consider seeking support, whether through therapy or support groups, as addressing these feelings can help you find a path toward healing and self-acceptance. It might also be beneficial to explore healthier coping mechanisms for the emotions you are experiencing.