Pimples turn to brown spots (darker than my skin colour)

I had a pimple on my face, and I popped it. As stupid as that is. This little piece of skin, I think it was, fell off and then I put on antibacterial to clean it up. Later, it turned to this brown spot, with no bump. Like it's become part of my skin. I have other smaller pimples around it and they don't go away, no matter how much antibacterial I put on it.

Help? I don't want them all over my face!