"if the gut flora is out of whack and damaged i don't think a juice fast will reverse that and bring it back to complete healing within 7 days?"
You are right about that.
You are not going to fast 7-10 days to cure gut flora.
Gut flora reacts to whatever comes through your mouth.
You are going to fast to find out if your everyday diet is a cause of all or just some of your major symptoms.
Lets say you are new to everything, you just arrived to this board, and you read 5 success stories where people cured their peeling lips by eliminating from thier diet whatever they are intollerant to.
You read that some people cured it by eliminating wheat, other cured it by eliminating all gluten, other eliminated meat, or lactose, or Sugar or eggs or sulfites or Sugar etc.
So, you start reading about Rotation - Elimination Diet but it all sounds very compicated and very difficult, so yo get scared of it and you give up before you even try anything.
Bad move, but common move. 80-90% of people fall in this category. Rotation - Elimination Diet sounds too complicated to 80 - 90% of people.
Juice fasting is only a few days warm-up for the real water fast.
If the cause of your symptoms is inability to tolerate someting you are consumin every day or at leat every week, someting like gluten, milk, eggs, wheat, meat, sugar, sulfites , benzoates , sorbates , corn syrup, grains, corn etc... and you start fasting, you will eliminate from your diet just about everything you eat, except water.
When water fasting, the water should be the cleanest available, your local tap water, more often than not, is not good enough.
My experience with people suffering from eczema, acne, EC peeling lips, psoriasis, hives, allergies, Seborrheic Dermatitis , folliculitis, dry skin, itchy skin, cracked skin , IBS, IBD, other chronic problems etc... is: if they are intollerant to something in their everyday diet, and if that intollerance is major cause of their symptoms, and if they start fasting, while in the same time making sure intestines are flushed out clean during the first few days of fast, their symptoms will improve within 7-10 days at least 50%, sometimes even 100%.
If intestines are NOT flushed out clean, some of the foods from the past diet may stay there for weeks, and will definitively messup the results of fast, wasting the good fast.
Psoriasis takes almost always longer to improve than eczema. Acne may dry out in 5-7 days.
Lips EC may significantly improve in 7-10 days. Seborrheic Dermatitis may improve in 4- 5 days.
Symptoms of IBD disappear in a few days.
Juice fsting may not be enough, if you are intillerant to carrots, beats or whatever juice you are drinking.
That is why at least 7 days on water will give far better answer.
It is not a cure all, it is a diagnostic method.
It answers one very important question:
Are the symptoms you are experiencing caused by intolerance to something you are eating almost every day?
If your condition imroves, even just 30% improvement in 7 days, the answer to the question is: YES! Your diet contains something you are unable to tolerate.
Now that you know the answer, you can continue with rotation - Elimination Diet following your fast, and pinpoint exactly what it is.
Considering there are many people having problems with wheat, gluten, milk, eggs, animal meat/fet, sugar, sulifetes, sorbates , benzoates , etc... you would continue your new restrictive diet without those foods for a few weeks longer.
If your condition continues improving, your answer YES will be even more sure.
After several weeks on restrictive diet, you would add just one of those foods into your diet, and you would observed your reaction.
If no reaction to eggs, eggs are good.
If no reaction, the food is added to the white list.
If negative reaction, the food is added to black list, and you would not try re-introducing it until you try FMT or Liver Flush or yogurt or kefir enema.
If your condition show now improvement during fast, it could mean you are allergic to your cat, or your wallpaper, or the fire retardant in the mattres you are sleeping on, or fire retardant in the carpets or paints in your house or whatever else you are in contact with.
It could be something in your water.