This is an extremely peculiar situation for anyone to comment on. We don't know about the feelings that you have for him, I'm assuming the person's a guy. Although, speaking personally, you shouldn't mind much if you have a feeling of likeness towards him.
"Hi, babe [or baby]," could suggest lots of things, from "You're very dear to me" to "You're very sexy, to me." You would have to decide how appropriate it is after 5 minutes, 5 hours, 5 days, or 5 weeks, and also the circumstances-- how public or private, etc.