This marks the first time Dexter has ever said the words "I love you" to another person other than Harrison.
Jordan Chase (Jonny Lee Miller) wears a necklace containing a sample of blood. Miller was previously married to Angelina Jolie who very famously wore a vial of Billy Bob Thornton's blood whilst the two were married.
While there are persistent myths about supposed "hangover food", hangover headaches are actually caused by brain swelling due to alcohol-induced dehydration. So a better remedy than eating any kind of food is to drink (non-alcoholic) fluids.
The title is a reference to The Who's song Baba O'Riley, whose title is in turn a reference to Woodstock.