Hi there, I had mine out when I was 16 and I was in agony for a fortnight. The pain got so bad I had to go to a&e to get liquid painkillers. Apart from pain in the throat I had no other problems and would go through it again as aftter you heal, you have a life free from that awful infection. I stayed in hospital overnight and had to eat toast before going home. My advice is cancel the concert (will also lesson the risk of infection which is not good!) and plan a good few days of dvd's, magazines etc, ie, doing nothing!
Good luck.