It was a series, possibly a trilogy. I would have read it around 2005 from the local library. I have a feeling it may have been from the 80's. Was a paperback and I think each book was a different colour, I'm thinking dark purple, green and blue with maybe a sort of wreath design on the front?
The main character was a woman who was an outcast. People had their clan/tribe/nation's insignia tattooed on their earlobes with special ink from a creature's claws when they were babies/children. I think some also had gemstones embedded in their ears like piercings? Those without tattoos, like the main character, are shunned and seen as a burden on society, so much so that they are sterilised as young adults and branded.
The different ~clans may have been different islands? There was a class system where certain tattoos were more highly regarded than others.
I think criminals had their earlobes cut off so that they became outcasts.
Does this ring any bells for anyone?