Could a micropenis be a consequence of a errored circumcision?

No. Micropenis is diagnosed based on penis size, and is usually due to hormonal issues during development. It has nothing to do with circumcision.
No. "botched" circumcisions can result in persistent redundant skin if too much remains or penile entrapment if too much is removed. However, the length of the penis cannot be altered by the procedure unless the penis is partially amputated.