It would not do any significant harm to simply/carefully(!!) grind down or adjust the buggered section of thread. A ham handed user of the chaser taps
could do a lot of damage if the tap starts wrong and begins to cut a new set of threads. The BB cups will have enough thread engagement left if you
remove the offending part of the thread. I did this recently on a DA freehub that I managed to bugger about 25% of the circumference on the first two
threads by cautious use of a ball end dremel tool and salvaged the freehub, which has a lot less thread engagement on the cassette locknut than a BB.
A BB threader such as pictured rightly used would make short work of the buggered thread.