I'm a male photographer, I don't know anything about makeup. I was just wondering if a model were to use a concealer to cover pimples, would the concealer do enough not to need photoshopping? Or would photoshopping be needed anyway, because the bump of the pimple would still be picked up by the high resolution camera?

You'll need to photoshop it anyway. Concealer will hide redness and even out the skin tone but it won't hide the actual texture, so the shadow from the pimple might show up on the photo.

Thanks