How To Avoid Croaking Voice?

Hey i love metal music and i have tuahgt myself how to metal scream my fav band i9nclude arch enemy , slipknot and the hard head banging stuff i have tuahgt myself it by watching my idol Angela gossow from arch enemys vocal leasons and im doing very well yet sometimes my throat sitll hurts for a while after and my talking voice kinda goes all funny like coraking is that okay or is it bad?