As you recover from your breast augmentation, you want to make sure you are comfortable, rested, and able to recover in a safe environment while continuing to follow the post-operative instructions given to you by your plastic surgeon (medications, ambulating, etc). It would not be a wise if you are standing for several hours in a crowded area where people may be bumping or pushing you, or placed in any situation which may aggravate your surgical site and healing, but a small local venue with a short concert in comfortable seats can be a completely different situation. Discuss the details of this concert and your healing progress with your plastic surgeon who can better advise you on whether you should go or not.