Actually, you can wear glasses to a concert. If you don't wear it, you may miss some wonderful details. Also, if any emergency happens, you can react to it rapidly. However, to avoid pushed by some crowd people, you had better not to wear glasses. Thus, the best choice for you is to wear contact lenses.
Well, it seems that the concert you are going to attend is quite formal and serious which aroused your concern. I mean, sometimes, there are some occasions which requires formality and seriousness, so you should carefully check your clothes and appearance. However, a lot of people are near sighted, thus, glasses become essential, but as you can see, Trendy glasses are not suitable in that occasion, so I recommend acetate glasses to you, which seem to be formal .
You don't already own contacts? You don't own those rubberized prescription sports glasses?
I think your best bet is to go buy a slim, hard case for your glasses. Before you go into the pit, take off your glasses, put them in the hard case and slip them into your pocket. When you want to actually see the band, leave the pit and put your glasses on. Same thing applies to crowd surfing.