There are rashes that can complicate the diagnosis which is why sometimes doctors will feel the need to either culture the fluid from lesions and/or perform blood tests to confirm herpes.   It's a tough call on when you have 'active virus" because experts have found viral activity in the absence of a rash; you can also have tingling, pain - no rash and have active virus in bodily fluids.  It may also be really hard to tell when a recurrence is truly over and the virus inactive. Yes, the rash can last that long and then once the rash begins to resolve you may still have redness or signs of inflammation in that area.