'Oh well I saw you at the doctors waiting for a test
you tried to look like some kind of heiress but your face is such a mess'
My interpretation of this is that his girlfriend cheated on him and got pregnant with another man and now she's left to bring the child up on her own. The narrator is revelling in her misfortune and thinks its punishment for her cheating.
To add to the pregnant theory:
'Oh well I saw you at the doctors waiting for a test you tried to look like some kind of heiress but your face is such a mess'
My interpretation of this is that his girlfriend cheated on him and got pregnant with another man and now she's left to bring the child up on her own. The narrator is revelling in her misfortune and thinks its punishment for her cheating.