In Mass Effect 2, Shepard's physical appearance (especially when you decided to go Renegade) could end up changing pretty drastically, though you could permanently reverse it if you chose to.
Does this behavior continue in Mass Effect 3? I'd like to know so I can customize my character's appearance accordingly if this is going to happen again, especially if she's going to end up with Terminator eyes…
Best Answer
Yep. Renegade sheps will see the same trademark fire red facial scars and red eyes.
Random screenshot:
However, the scars and glowing eyes are based on your current, ME3 alignment. Since even a full renegade bar from ME2 only amounts to a token chunk of Renegade points, Shepard will always have minimal scarring at the start when imported, regardless of whether you upgraded the Med Lab in the previous installment.
Consider it a result of the 'low stress environment' that is an Alliance brig awaiting court martial.