Vince Neil -- The Show Must Go On ... Even With My Broken Foot!

Despite the fact he has two broken bones in his foot, Motley Crue frontman Vince Neil is REFUSING to bail on his concert tour ... insisting he'll sing through the pain.

Neil fractured two bones on his left foot while performing at the Blossom Music Center in Ohio Wednesday night ... and tweeted a pic of his swollen foot before he went to the doctor.

Neil has since had the foot put in a cast ... but tells TMZ nothing will keep him from hitting the stage in Toronto tonight ... even though he'll have to tone down the physical stuff.