I really don't think you screwed up, BUT, I do think you have a professional obligation. IF he is a paroled sex offender, than, that is a matter of public record. There isn't any confidentiality requirements to be concerned with.

I don't know of any privacy laws that would prohibit your call with specific details about his past. After all, that is the 'problem', not his medical care/treatment, which would be privileged. IMO.