Verified answer

You could be sick, I'd take a break from screaming and growling for at least 2 weeks and keep up on all fluids. For your vocal chords however, I'd recommend hot honey tea with a little lemon. Perfect to keep your vocal chords up and running the way they should be. Also, eat honey by itself. When you were a kid, did you ever chew bubble gum, put it in your hands, and roll it up into a ball to see how much dust and dirt you could collect? That's what honey does for your throat. Move it around before you swallow it. It gets all the gunk and bacteria that could be causing the raspy sound.

On the other hand, don't scream from your throat. You could do some serious damage to your vocal chords and your throat. Coming from one musician to another, (and I mean well when I say this, I'm only trying to help and isn't meant to be taken offensively) but this is why most screamo and metal bands don't last very long is because the singer is screaming. Screaming is not singing. In fact, that's the best way to increase your chances of nodules on your vocal chords which causes most singers to stop singing altogether. Screaming ruins a lot of metal bands. It doesn't have to hurt to realize that it might be doing some damage, especially if it sounds scratchy. If you acknowledge that there is a problem in your "singing" then it might be best to take a break from it for a while or move on to a different genre, one that won't mess up your vocal chords as much.