There's no such thing as herpes complex. There's only two types of herpes simplex, herpes simplex type 1 and herpes simplex type 2.
Intercoarse or oral sex with someone who has a herpes blister or a common cold sore on their mouth.
Root someone with herpes.
Human herpes virus type 3 (HHV-3); see related link for information on the virus.
Yes you can. Like all diseases there can be a complication with the disease.