Therapy works temporarily for 6 months , stuttering is like a cancer .It comes back vigorously. No treatment whatsoever. You need to relax ,get away from toxic environment, need the constant encouragement from good people, parents need to support, get self motivated and say " I can better than others ,always" , never care attitude towards stammering and other people opinion on it,. You need to focus on your happiness and live your life ,forget this stuttering virus"