The Phantom of Paris (possibly another sequel) 

If this is what I'm thinking it is, yeah, it's a sequel. I read it back in high school. I don't remember much about it except that you never heard from a secondary character for more than about 3 pages before they vanished forever, and that Erik found Jesus. Which was kinda freaky. If you're wanting decent sequel go for Progeny, or Journey of the Mask (still a little terrible, but at least interesting).