Hi Nima! I am not a doctor, thought I should start off with that. I have a friend at work who has been struggling with shingles for over 6 months now, so depending on how bad your case is you may want to weigh which is worse - the starch from the meds temporarily triggering your as, or the shingles progressing. Some cases can be really bad, but as you are so young it may not get that serious this time. As far as how long it would take you to get back to where you are after eating starch, I am not sure.

That all being said, I read an interesting article recently on vitamin C dosages, as I've been thinking of adding it to my daughter's list, and one of the things they listed as it helping was shingles. So if you don't want to do the standard med, you may look into vitamin c (probably in the form of ascorbic acid to avoid starch in pill form?). I'm assuming your doc wouldn't be interested in giving you the injected form, but there are supposed to be ways to determine what your tolerance level is to vitamin c. Here are some links that are very good at explaining it all, if you're interested.

http://www.healthyimmunity.com/qanda/31-Shingles.asp

http://iom.edu/Activities/Nutrition/SummaryDRIs/~/media/Files/Activity%20Files/Nutrition/DRIs/ULs%20for%20Vitamins%20and%20Elements.pdf

http://www.sott.net/article/265993-Vitamin-C-shingles-and-vaccination

Best of luck with the diet, and the shingles. We're still working on getting our diet to fully do the trick, but it does help keep the pain level lower than when we started.