If you are saying she has constant diarrhea, her bowel flora may be off and probiotics may help. It always stops diarrhea for my friends. I believe if she blisters, she may be eliminating candida and could use topical Colloidal Silver for that. If these two things work, you might want to give probiotics as a preventative until her BMs are absolutely normal.
I would look at a change of diet, if it were me. Whatever she is eating, change it and see what happens. Also, note if she has been eating anything new the last few days.
If it were my daughter, I would hold back on solid food for twelve hours or so, giving only water or mint tea, and give food only if she asks for it.