You're damaging your ears permanently every time you gig with no hearing protection unless you guys play really really soft and low (Sure...).
If I were you, I'd worry more about the long term than next Wednesday. While you may not be seriously impaired later on, you're definitely going to suffer hearing loss and loss of the ability to hear certain frequencies. As a musician, that sucks.
If you're already experiencing drastic effects, however temporary they may be, it's cause for concern and calls for a change in your gigging habits if you intend on retaining your proper hearing in the future.
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