She really was going to sing Neon Lights again? She's already sang it on the Tonight Show with Jay Leno. Sure it's Jimmy Fallon now but it's still the tonight show.
Her speaking voice on Jimmy Fallon sounded so rough and strained

Thankfully they were playing a drawing game where very little talking was required on her part. She really didn't sound like she should be talking at all, let alone singing.
We know Demi can power through and sing sick a LOT. I think she's been doing that for weeks now. She truly sounded like she's on the verge of being completely voiceless. I think tomorrow's concert is going to be South America 2012 levels of nearly lost voice, only more noticeable because the crowd won't sing loud enough to completely drown her out.