The Bon Jovi concerts I go to are always in my exam period. But my advice is: go to the concert. I always did, and I never had bad feelings about it.
The worst time was when I had an exam of Economy the next day. I had an exam period of 15 exams because I didn't pass the first time and Economy was the toughest one. So I had studied a lot for it during July and August and the day before the exam I went to the concert and enjoyed it a lot. I could sing and scream away all my worst feelings and stress.
I was home at about three at night and then at seven in the morning I had to get up again to do my exam at 8:30. I was very tired and I didn't pass the exam, but after it I felt so good because I had seen the guys that the rest of my exams went very well.