Suggest Treatment For Chronic Pain Due To Nerve Damage

my wife suffers with severe nerve damage and is in pain 24/7 she cries and screams with pain the problem is she can not have pain killers which contain ibuprofen and morphine and morphine based tablets make her violently sick.Her Doctor says there is not a lot he can do as we do not know enough about the nerves in the human body to fix the problem,nerves will mend but not if they are cut away.She had an accident as a child over 30 years ago which left nerves exposed and hanging out,these were cut stuffed back in and sewed his is where the problem comes from please help,is there a pain killer that she can take which will not make her ill thank you.