Many moons ago as a young 'un, hair of the Dog was the only way to go, can't really say it cured a hangover as such, just kept the Alcohol levels up, thereby avoiding a hangover
But ooh, when it did kick in, not pretty, paracetamol & a lie down in a darkened, quiet room.
Bit difficult in a Barracks though, slagged unmercifully for being a Wuss ! Fact that this "Wuss" had stayed out longer and drunk more & harder than my detractors ! Ah well !