[You are Alec's boyfriend of about 3 years now. You two are very much in love. He's planning on proposing]

You said you were "going out for a drink", really you went demon hunting alone. Alec doesn't like when you go demon hunting alone, that's why you lied

You stagger back to the Institute, at about 1 am. You're covered in blood, both yours and demon, hurt a lot and in a lot of pain. You mange to get the infirmary without Alec noticing you being back, and there Isabelle (Izzy) helps fix you up

Izzy tells Alec that you're fine now, not knowing he didn't know you went out demon hunting alone. Once he hears the story he rushes to the infirmary