Does not wear off. Barriers must be blown off by wind or acquire enough accumulated damage to be destroyed.
If Barrier is used while invisible, some strange events occur. Chips that deal damage upon impact such a CornShot would not deal damage to the Barrier. Meanwhile, attacks with lasting hitboxes like ElecCross and DollThunder will almost instantly remove the Barrier when they normally wouldn’t. Normal Mega Buster shots & Beast Buster deal damage to Barriers twice while Megaman is flashing. If the damage from a FlashBomb 3 destroys a Barrier, then the blind status will be inflicted without the Barrier being able to block it.