Skillfully try to tread it back in yourself. I recently had a BSA threaded bike with the cups threaded into the wrong side of the frame. Yep....left hand threaded cup in the right hand threaded side and the right hand threaded cup in the left hand threaded side. I removed them and threaded them into the propr side with no need for chasing the threads.

If you have patience you can catch the correct thread with the cup.