Subepidermal images of the user may be used to assess subepidermal features such as blood vessels (e.g., veins) when the device is attempting to authenticate the user. The subepidermal features may be compared to templates of subepidermal features for an authorized (e.g., enrolled) user of the device. Assessment of subepidermal features during the facial recognition authentication process may be useful in distinguishing between users that have closely related facial features (e.g., siblings or twins). In addition, assessment of subepidermal features may be used to prevent unlocking of the device by an unauthorized user wearing a mask or using another face replication method.