Whitened mortar...
 

Need to know what to do with mortar in between stone veneer that is whitened in a section that the contractor scraped too much. It was too high and when he knocked it down with the finishing tool/bristles, it is now almost pure white where the rest of the mortor is tan/grey. Contractor will not return calls. Thanks in advance.

My first thought is that the contractor did the scraping in response to a complaint. And the cure often turns out worse than the disease.

In any case, time and dust will age mortar joints to a more uniform appearance.

Let it oxidize.