Just looks like lyrics someone wrote for a song to me.
What type of literary device is this lyric, if it even is one: "Don't lose who you are in the blur of the stars"?
It's metaphorical because the lyrics are saying that 'who you are [might be] lost in the blur of the stars'. You can't literally be 'lost in the blur of the stars,' so it's means something else: The busyness of everyday life or something similar.
I have no interest in the creative side of English composition, so I don't know enough to actually answer and I am not interested in learning enough to try to answer.
On the other hand, this site might be useful to you: