My guess is that you went all the way around the thermometer and back around to 250. So you had it pretty hot! Depending on the gasket you should still be fine. Just start over and keep a little bit better of an eye on the temo till you get it closer to the temp you want. You will get it in no time! Good luck.
I would agree with both NOLA and Lous on this one. Don't brine it if it is enhanced, it will over salt the meat. Cherry leaves a great color on the bird. I also us a small amount of apple with mine. I love the smell of applewood smoke in the morning! Like Lou said, don't use too much wood.