If it was a few hours later, I'm assuming you just puked up a small amount of stomach fluids?
Nausea can be a side effect of opiates. Morphine is notorious for causing nausa, and the reason why the synthetic opiates were invented was to try to make opiates less likely to cause nausea.
You could just do it without the Percs, especially since that last video from Dr. Death mentioned that sodium nitrite might be more peaceful than previously thought. But even if you take the Percs and puke a few hours later, it shouldn't matter because the nitrite will have been absorbed by then. Some people puke while they're passed out after taking N, but they still die.
