Yes, the ego and the self are the same thing.
Aldous was experiencing the absence of the ego from the effects of LSD. It is rare but others have experienced the absence of the ego without taking drugs. I have had that experience myself although the event would take too much time to relate here. It was the results of metabolic shock.
With the ego eliminated you have absolutely no fear, which indicates that fear and the ego (self) are tightly interrelated. In fact, when my ego (self) was eliminated it was an absolutely joyous experience. I was no longer "Alan Turing" (not my real name). My impression is that a lot of energy is used to maintain our selves in our bodies. All that energy is released in an entirely pleasurable way when the ego is suddenly eliminated. Aldous didn't experience the sudden loss of self as LSD takes time to produce its effects. So for Aldous the self was gradually eliminated.
When the ego is eliminated there is still awareness and creativity processes in your mind. In other words, awareness is not the same thing as the self. But the awareness is totally non-judgmental. You could care less whither you live or die; both are equally attractive and possible. This is the reason why one should never take LSD by themselves. Not only is it now illegal (it wasn't when Aldous took it) but you need someone as an observer who does not take LSD to monitor the person taking it to prevent them from doing something dangerous.
This illustrates why we have an ego or self. The main function of the self in our bodies is to protect ourselves from possible danger. The self is not very smart however. It is there to prolong the life of the body as much as possible, its evolutionary function. It is easily confused by promises of eternal life from religions. Most people's selves are unable to realize that a promise of eternal life is not verifiable. And that is the reason why we have such absurd religions dominating societies.
Those eastern religions that attempt to eliminate the ego also know that the ego is a necessary part of the human mind. Necessary to keep us alive.
Aldous L. Huxley wrote two books on his experiences. In addition to "The Doors of Perception" he also wrote "Heaven and Hell" in which he explored the heights and depths of human awareness. I think he misinterpreted what was happening. I've read everything he ever wrote and have a great deal of admiration for him. I even wrote an essay once comparing his philosophy to that of his grandfather, Thomas Henry Huxley.
Note to Mantrid: The myths of LSD abound. Flashbacks may occur with a few mentally unstable people but not most. To worry about the unseen being seen is to worry about knowledge. It is not a very strong argument for ignorance. But I don't want to be intrepreted as advocating breaking any laws.
Note to Yaoi Shonen-ai: Freudian psychology has generally been discredited as a quack science that cannot be verified. I can assure you that you can still have awareness after the ego is eliminated just from my own personal experience.
Oh, I should mention that the chemist, Dr. Hoffmann, who discovered Lysergic Acid Diethylamide died a few weeks ago. He took the first LSD "trip" on his bike on the way home from the lab after he accidentally took a micogram amount of the chemical. I corresponded with him briefly many years ago. Very pleasant gentleman.