As the symbol of the Post-War Man, Hal Jordan naturally went head to head with the issues feminism and female empowerment. In any head to head conflict, Hal's head takes a beating and this one is no exception.
Carol Ferris personifies post-war female empowerment. During WWII, as able-bodied men were swept into the armed services, women took their place in the workforce, ushering in the modern era of women's socioeconomic independence. Men's return from the war and their expectation that women would return to "their place" in the home caused friction, and introduced a complexity in male/female relations with which society still grapples.
Carol Ferris, in her dual role as Hal's (principal) love interest and boss, encapsulated the conflict nicely. When she was further "empowered" as Star Sapphire by the female warrior race of the Zamarons, she was pushed to use her power to humilitate and subjugate Green Lantern (although deep within she secretly wanted him to win out over her).
HA! The joke was on her, silly female; Green Lantern is quite capable of humiliating himself, thank you very much. Watch out for those projecting ledges, Hal; they're everywhere.
Basically, Hal can't handle Star Sapphire, empowered woman, any more than he can handle Carol Ferris, empowered woman. In fact, if it weren't for the fact she suffers internal conflict over whether she wants to beat him or not, she'd kick his silly arse halfway to Star City and back. Through Carol, the writers are saying, "Thank the gods women can't make up their minds whether they want to bring us under their thumbs to make us behave or to have us be all Alpha Male so as to protect them, otherwise we guys would be in deep doo-doo."
And that's what it means when Hal hits his head, recoiling from the power of Star Sapphire.
That, or that he's a total incompetent.