Answer:
A metaphor.
Step-by-step explanation:
A metaphor is a comparison between two things that are completely unrelated, but share some common characteristics in the point of view of the author. It may provide clarity to the idea the author wants to transmit.
They are very used in poetry because they are a way to communicate complex images or feelings.
In the excerpt what the author is trying to express is that life is like a flower, beautiful, but have thorns that can harm you, these thorns are a metaphor of the bad things that could happen throughout the life especially in the romantic field. By saying "I bleed!" is also inferring that it was emotionally affected.
I hope this answer helps you.