Is your wife having real pains or a stinging sensation? If it is the stinging, cut the amount of Grapefruit-Seed-Extract in half and then add a drop a day to a tolerance level. I did have stinging and felt that the Grapefruit-Seed-Extract was killing parasites or bacteria.
If she is having real pain, I have a thought about that. People who used Cansema Salves (they actually kill the tumor using bloodroot), had a lot of pain, but that was also accompanied by success in getting rid of the tumor. I recall some stated that on a scale of 1-10, some said and 11 couldn't describe it. Many used ibuprophen or aspirin, if not pain killers from their doctors.
Your wife will have to decide it the pain is a healing pain, or a detrimental pain. Either way, the Grapefruit-Seed-Extract is killing something because that is what it does. Wish I could be of more help with this issue.