[zamler]

Acid is about the worst thing you can put on concrete, because concrete is alkaline in nature. Concrete contains calcium hydroxide which is what was probably attacked and caused the discolouration. I doubt there is much you can do short of putting a topcoat to hide the damage.

There are products to colour concrete that are in fact an acid, you might want to consider doing an acid etch it might make the stains you have blend in.