Is the back camera what I look like to others?
Back camera is how you look from other people, and typically shot from distance people normally see you, so perspective will be also likely going to be close.
Does the back camera show the real you?
No, it definitely does not make a huge impact on how you look in reality. Your mirror image is the reverse of what people actually see you as, but the majority of people won’t be able to tell the difference between you and your reverse image.