Mischa Barton seemed to have trouble orienting herself at the G- star after-party at the Bowery Hotel. Barton — who recently attributed an involuntary hospitalization to wisdom-teeth complications — stum bled up to the check-in table with a posse of eight. “She kept saying, in a really spacey, weird British accent, ‘Like, I’m with the deejay. I to tally know the deejay. I’m here for the deejay,’ ” laughs our spy. “She was slurring her words.” After being let in, we’re told that Barton “needed to be escorted to the deejay booth” where she proceeded to “stand for about an hour, dancing in her own world. I don’t think her eyes were open to full capacity — or even half capacity — the whole time she was there.”