Older Woman?

B-b-b-bruises cover your arms
Shaking in the fingers with the bottle in your palm
And the best is (best is)
No one knows who you are
Just another girl
Alone at the bar

I think this same girl is grown up and is now older. From the first line, it seems as if she gets beat by her sexual partners or possibly even a boyfriend. The next line may indicate that she is an alcoholic now. She has the shakes so it could be a possibly withdrawal from alcohol or she may even be rattled because she just got the shit beat out of her.

The artist seems to be happy that she is feeling shitty. This girl may be the girl he was talking about in the beginning of the song. He obviously has hard feelings toward her since he says 'and the best is/on one knows who you are" He is probably getting gratification from this fact.

The last two lines may signify that she is alone now. Everyone she knows has deserted her. Since she is not at "hot" as she was her sexual partners probably have left her and the person that truly cared for her, the artist, has left her too. She is all alone at the bar drinking her life away. She may even have a STD. A nice reminder of the fun she used to have. But that is just an exploration into her life. The lyrics really don't point to her having a disease. She fucked up. She got what she deserved, in my opinion.