I believe that a lot of what has to do with singing is dependent on overall physical health and relaxation. The Alexander Technique would be helpful to you i think, because it emphasizes coaxing not forcing your voice to return.
The main thing is to keep from abusing your voice through strain. Finding the proper balance for your voice and not pushing it beyond those parameters is important.
A throat specialist can tell you what is wrong but not how to correct it. For this you need a special kind of voice teacher. Someone who can help you relax and find the right balance.
Diet and proper excercise is essential also. Avoid excercise that produces any kind of strain. Aerobic excercise and deep breathing (perhaps some Yoga) would be helpful as long as there is no force.
It's not so much a matter of losing your voice but uninhibiting it so that it is again free to work for you.
Unfortunately, the demands of a rigorous role in some of the modern type rock operas can stand in the way of uninhibited vocal production. A search for that special type of voice instructor is essential to guide you through the rough waters.
Avoid dairy products, anything such as lozenges that dry up the vocal folds, and get a lot of quality sleep, moderate excercise and relaxation techniques should help a lot. Drinking enough water is helpful. Pee clear. But most of all, take away the strain and abuse.