Breezy's right.

There are a number of good threads on this topic, which you should be able to access by typing "voice" or "singing" in the Forum search box at the top of the main page. However, for some curious reason I can't get it to yield anything, though I KNOW they are in there. Anyway, below is a link to an old thread I had in my personal tracer, which should start you off. The Mudcat member "Alice" is an expert in voice matters, and there is a lot of good advice on offer which can be of great help.

But what it can't do is work miracles - I think you pretty well summed up the situation when you wrote that there is no way to sing in that style (i.e. screaming and growling) and not destroy your voice. It strains and abrades the vocal cords, causing damage that will eventually become permanent, and I'm really afraid that home remedies - or even professional medical ones (who will all tell you to stop singing until you're healed) - will not solve the problem, which is being caused anew every time you do a gig. I'm sorry this answer is such a bummer, but offering false optimism will do you no favours. You really need to make some serious decisions about what you want to do with your vocal future while you still have one. Anyway, try the search-the-forum feature and take a look at THESE links. And - best of luck.