During the recording of the upcoming release of Social Distortion, lead singer Mike Ness was diagnosed with stage 1 tonsil cancer. Read about it here.
It seems as though he's mostly fine, and that it was both caught very early on and is quite treatable. There's some great quotes in there, throughout which Mike remains very positive, so I think we're all good, but they did postpone the new album and tour. He'll need some time to recover, but it seems there's no stopping Social Distortion!
To be honest, Nevermind probably has had more of an impact on punk and pop punk than Dookie, just introducing alternative music to the mainstream as a whole. Stylistically? Not at all. But from the perspective of introducing music more like that to the world, Nirvana is your band.