its not known, Haku tells her not to luck back and she goes its not known what he did... I think they might meet again since Haku did promise that to her
I always believed that Haku and Chihiro would meet again. And even if Chihiro forgot, memories can be hard to recall but never forgotten (Zeniba). So she would remember eventually. And Haku would do anything to meet Chihiro again, because he loves her.