Is the self the ego?
The ego is seen as the center of consciousness, whereas the Self is defined as the center of the total personality, which includes consciousness, the unconscious, and the ego; the Self is both the whole and the center.
What exactly is an ego?
Your ego is your conscious mind, the part of your identity that you consider your "self." If you say someone has "a big ego," then you are saying he is too full of himself.