While we do know that in real life, binge drinking can result in memory loss, this doesn't really fit the pattern established in the comic so far. Andrew has never lost memories just from drinking alone, as evidenced when he wakes up with a hangover after his first night dining with the Samaras family:
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His first two instances of memory loss followed immediately after meeting with Joanna and falling deeper into character as Elena while under the influence of whatever she drugged him with (which seems to share a lot of the same properties as rohypnol):
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He met with Joanna one other time during lunch with Dimitra, and shortly after that he had the romantic interlude with Nikos, which I would definitely characterize as "falling deeper into character". I'm wondering if he was drugged again during this lunch. Is this why he was so eager to sleep with Nikos? Is he going to remember any of it? We're currently in a flashback inside a dream, so we won't know what Andrew remembers until he wakes up.
So if we follow this pattern, I'm guessing we're going to see Joanna pop up again very soon. If she drugs Andrew again toward the end of this flashback sequence, it would explain the memory loss in the screenshot you posted, and it also might explain a lot of Nikos' behavior afterward too. My theory is that while drugged for the third time either during or after the salon visit, Andrew falls deeper into character as Elena and flirts aggressively with Nikos, in a manner that is not necessary merely to preserve their cover. Nikos perhaps interprets this behavior as Andrew sincerely coming on to him out of character and he now believes that Elena is who Andrew really wants to be and that she wants to be with Nikos. And yes, alcohol was probably involved in addition to Joanna's drug, though it's possible that the drug itself could account for the hangover-like symptoms.