There is no such thing as a chemical lobotomy. That is a made up term. Flat affect can be a result of the schizophrenia itself, rather than the meds. Look up “negative symptoms of schizophrenia.”
From Wikipedia:
Negative symptoms are deficits of normal emotional responses or of other thought processes, and are less responsive to medication.[10] They commonly include flat expressions or little emotion, poverty of speech, inability to experience pleasure, lack of desire to form relationships, and lack of motivation. Negative symptoms appear to contribute more to poor quality of life, functional ability, and the burden on others than do positive symptoms.[22] People with greater negative symptoms often have a history of poor adjustment before the onset of illness, and response to medication is often limited.[10][23]