Charlie's view of himself changes in the novel Flowers for Algernon as his IQ increases. His view of himself changes again in the latter part of the story as he returns to his prior IQ level.
Initially, as Charlie gains knowledge after his operation, he begins to see the world around him with a greater clarity. His understanding of people’s motivations in their past treatment of him becomes clearer. Specifically, he recognizes that many people whom he had regarded as friends were, in fact, only mocking him and encouraging him to do foolish things just so that they could laugh at him. He sees a parallel with the young boy who gets mocked and taunted by others and loses his temper, as he recognizes his pre-operation self in the situation.
The irony about Charlie’s intellectual ascent is that while he can see more clearly how the younger Charlie was treated badly and did not understand it, the more intelligent Charlie loses some of his emotional sensitivity. He loses insight into how his greatly increased intellect affects and intimidates others. He embarks on a relationship with Claire only to pass her by intellectually and to lose patience with her inability to keep up with his rapidly ascending mental acuity.
Once Charlie sees what has happened to Algernon and realizes that his progress will also begin to reverse, he feels pressure to complete his work quickly while he still has the mental capacity. Emotionally, he does not want others to pity him as he begins to descend again, although he seems to pity himself. When he blunders by returning to Claire’s classroom, he is embarrassed and chooses to leave so that he can start a fresh life with people who will not know that he once reached a much higher level of intellectual capacity.
Charlie experiences a lot of change throughout the story, so much so that it's fair to say that he's not the same man at the end as he was at the beginning. For one thing, Charlie is so much more worldly-wise, less naïve about the ways of the world.
Having been subjected to ground-breaking scientific experiments, he's become more cynical, recognizing as he does that even what appear to be disinterested scientific advances can be distorted for selfish ends. Not unreasonably, Charlie feels like he's been used by Dr. Strauss and Professor Nemur. Essentially, he's been used by them as a guinea pig, and now that Charlie realizes that, he feels nothing but contempt for the whole process of which he's been a part.
After being chewed up and spat out by the ambitious boffins at the Beekman Center, Charlie gets his old life back. He may not be the same man as he once was, and he may be more intelligent than when he originally worked at the bakery, but at least life was much simpler then.
Even so, Charlie is anything but happy at the prospect of losing the extraordinary intelligence he acquired during the experiment. In fact, he's angry and bitter over it.
Charlie's view of himself changes a couple of times during the course of this classic story. At the start, he is a simplistic soul who has made a straightforward life for himself and is attempting to better himself by becoming literate. He considers himself far inferior to the adults around him.
After undergoing a research experiment that is intended to make him much smarter, he becomes far more self-aware and realizes that his "friends" at the bakery are actually making fun of him. He begins to see himself as somebody who can make a difference, as evidenced by his confronting Gimpy for stealing.
As his intelligence grows, he sees the adults around him as equals and discovers that he is capable of sexual desire. His self-awareness grows in leaps and bounds, and he realizes that Professor Nemur's intention was to prove a hypothesis—not to help him.
In answering this question, I am reminded of the old saying "ignorance is bliss." The more Charlie gains intelligence, the more he understands about his life and the unhappier he becomes. As he realizes how slow he was before the operation, he feels ashamed, and the realization that he has to go back to this way of life fills him with anger and despair.
Charlie starts out viewing himself as a child. He has little self confidence and little self-worth because of his lack of intelligence. He looks up to the adults in his life as godlike people who are far above him in status.
After the operation, as he becomes highly intelligent, Charlie gains self-confidence and begins to see the other adults around him as peers. He begins to perceive that they have flaws. They are no longer demigods that he reveres. For example, Miss Kinnian changes in his eyes from a revered figure to a woman for whom he has sexual feelings. He considers her enough of an equal that he can ask her out on a date.
Likewise, rather than looking up to Professor Nemur as before, Charlie realizes that Nemur took advantage of him out of ambition and used him as no more than a laboratory animal.
When he realizes he is going to lose his intelligence and go back to the way he was (or worse), Charlie experiences deep anger, an emotion he has not experienced before.
Charlie's view of himself changes significantly in Flowers for Algernon. Ironically, the more intelligent he becomes (as a result of the operation on his brain), the unhappier he becomes with his life.
The problem he experiences is that, as he gains intelligence, he becomes aware of several things that he wasn’t aware of before. For one thing, he realizes how slow he was mentally before the operation (or “operashun” as he wrote it). He looks at the man he was with something like disgust or shame. He also realizes that others who he thought were his friends actually took advantage of him and made fun of him at his expense. These realizations make it difficult for Charlie to feel true happiness.