Re: 'nor' or 'neither' ?
In BrE, I think "nor" is probably more common. However, the following are all correct:
Judy didn't come to the concert and nor did Carmen.
Judy didn't come to the concert and neither did Carmen.
Judy didn't come to the concert. Nor did Carmen. (For this to be grammatically correct, one person would say the first sentence and someone else would respond with the second sentence.)
Judy didn't come to the concert. Neither did Carmen. (Same as above.)
Neither Judy nor Carmen came to the concert.
Remember - correct capitalisation, punctuation and spacing make posts much easier to read.