Yoga poses caused tingling of hand+ twitching of finger. 3 week of yoga later symptom now less. did it help or did i kill off the nerve?

Interesting: From your description and history, yoga was not harmful. You did not kill a nerve. Degenerative disc disease in a 26 year old man requires exercise, posture training and review of your lifestyle. Yoga with an instructor that understands your condition would normally be a good thing. Breathing properly during postures can change the pressure on your discs. Inversion postures recommended.