Should you pop a blister, or just leave it?

I have a really big blister on the ball of my foot, and it is really painful. People keep telling me different things, so I'm not sure if it is better to pop it and put antiseptic cream on it, or just leave it alone. I can't walk on it, and I have work tomorrow where I'm gonna be on my feet all day. Any suggestions?? Blister plasters haven't helped, neither has a bandage =/