= "...your appearance...". I don't think it refers to feelings/ attitude, as you suggest. Although we don't have the full context from this brief extract.

It’s about appearance. It’s implying she is a narcissistic person, so if she likes her appearance and herself so much, she should love herself. I also think it’s implying a break up, it seems like he’s telling her to “love yourself”, not love him anymore or to forget him.

[Verse 1] For all the times that you rained on my parade And all the clubs you get in using my name You think you broke my heart, oh girl, for goodness' sake You think I'm cryin' on my own, well, I ain't [Refrain] And I didn't wanna write a song 'Cause I didn't want anyone thinking I still care I don't, but you still hit my phone up And baby, I'll be movin' on And I think you should be somethin' I don't wanna hold back Maybe you should know that [Pre-Chorus] My mama don't like you and she likes everyone And I never like to admit that I was wrong And I've been so caught up in my job, didn't see what's going on But now I know, I'm better sleeping on my own [Chorus] 'Cause if you like the way you look that much Oh baby, you should go and love yourself And if you think that I'm still holdin' on to somethin' You should go and love yourself