Laryngitis, the infection of the vocal folds that leads to the loss of the voice is a common occurrence. Sometimes, misuse, or environmental triggers are to blame.
In fact, most singers will face it at some point in their careers.
Old school thinking was that you needed to stop all use of the voice for a prolonged period of time. But just as we now get people up and moving much earlier after surgery because it helps prevent atrophy of many muscles and promote healing, so too, we also get people up and moving after laryngitis or vocal injury. The real question underlying the length of time you should rest is the extent of injury to the voice.
A simple rule of thumb might be to sing as soon as you can siren clearly again, without pain.
I came across a really good article by Tom Burke, a fellow Estill EMCI who also is a Speech Language Pathologist. I wanted to pass it along to you because he addresses the question of when to sing in a thoughtful and informed manner.
Great information for all of us as singers!