So if I understand well, he was rejected by the girl he confessed too, but even after acquiring mind control power, he settled to controlling his sister and his test subject without touching that girl, despite whatever happen in 57~62 (did he learn she's dating somebody else or something?I don't know about that part) that seems to be a turning point. Usually that girl would not be excluded.
edit: Thanks Thacker. Would upvote your comment if having posted my own comment didn't prevent me from doing so.
The title has 前編, or "part one." On the last page, 249, he says that now he's going to move onto to other girls including, naturally, the girl who rejected him. In 57-62 he finds out that she's apparently secretly dating a teacher, which pisses MC off because she's an honor student who tried to let him down gently by talking about how she was too busy to date at all with college entrance exams coming up, etc. Part two, if it happens, will certainly feature the girl who rejected him.