Shingles - How long will the rash spread

Saturday night I first noticed a small rash on my back.  Tuesday afternoon I went to a doctor and was diagnosed with Shingles in about 2 seconds flat.  At the time of the diagnosis, I had a few small red rash spots on my back, chest and underarm.  I was prescribed 4000mg of Acyclovir (800x5 times a day).  I've been taking my meds regularly.. but the rash seems to keep spreading.  On Tuesday (the day after I started Acyclovir) the rash was about 4x worse.  Today (Wednesday) it's still worse... how long can I expect the rash to continue to grow?

Since the rash is still growing, does this mean the Acyclovir isn't working?

Is there anything I can do other than keep the rash clean and covered with a cotton undershirt?  I'm staying home from work to avoid exposing other and rest up, but I can't stay home from work forever.

Aside from Acyclovir, I'm taking vitamin c, trying to eat healthy and drink plenty of fluids.

Thanks for any info or help you guys can offer.

[Matt7405]

Sorry, not sure how I did a double post -- please ignore this one.  If I could delete it, I would.