Try Activated Charcoal. This is a natural remedy that has been used for millenia to treat all sorts of ailments. It is highly adsorbent and will adsorb thousands of chemicals, pathogens, and more... It is non-toxic, and the worst that could happen is that she might become constipated, but only if she doesn't drink enough water after taking the charcoal internally (she should drink plenty of water afterwards). Visit www.BuyActivateCharcoal.com They have the products you will need if you can't find them at a local health food or drug store. Also, they have a lot of information available, and are very helpful, just send them an email if you have more questions.
I would have her take it internally using one of the following methods:
1.) Mix the powder form in water (about 1-2 teaspoon in 8-12 oz.) and have her drink the "slurry". This is the best method, but can be a bit difficult to get used to drinking. It is tasteless, but has a chalky consistency.
2.) Mix the powder in water and let it settle. Have her drink the water off the top.
3.) Mix it in with pudding or applesauce.
4.) She can take it in capsule form if she can't drink it or eat it (but it takes something like 12 capsules to equal 1 tsp. of powder).
Or get creative... just use whatever method you need to get it in her.
Also have her bathe in it (about 1-2 cups/bath tub). If she has open wounds from the hives/scratching, it may "stain" them temporarily, but it will not harm her.
Lastly, if she is still on medication. It is best to have her take it 1-2 hours before or after taking her medication so it does not adsorb the medicine before she has a chance to digest it. If you choose to use it long-term, it is best to have her take it 1-2 hours before or after meals also.
If her body is overloaded with toxins (which may be why she had swollen lymph nodes and is suffering from hives), charcoal should help clean her out. I would try this for a few weeks and see if she continues to break out.
Just a side-note, activated charcoal is a great remedy for diarrhea and vomiting (you may still vomit, but it helps get rid of the toxins that are causing you to vomit), bug bites/stings, and much more...
Hope you find some relief for her soon.
Sincerely,
H.