Since you were seeing the doctors and taking their medicine, your problem may be too complicated for someone to help you over the internet. It's difficult to tell how much, if any, danger you are in from stopping your medicines.
If you tell your doctors about your rash, they'll prescribe different medicines for you. You might think about giving them a chance to get you settled on medication that agrees with you.
You should have an evaluation by a professional herbalist before using herbal treatments. It's one thing to use herbs to build our health and another to use them in place of medicine for an urgent problem. Both really require experience and knowledge.
For now, eat wisely. You know the drill. Leafy greens, cereals, fruits, water. Eat as close to scratch as you can and as little processed foods as possible. And find a local herbalist to help you get your system in sync. Good luck, maude.
Try the American Association of Naturopathic Physicians (AANP):
http://www.naturopathic.org
Or the American Herbalists Guild (AHG):
http://www.americanherbalistsguild.com