The best treatment for the vocal cord damage is to take rest and the cords heal in 7-10 days.Steroids
are given so that the time of healing is reduced and the pain is less.
But after steroids you developed spasms etc , this could be because of the acidity caused by the steroids . did you take antacids with the steroids. ?
If not you should take antacids and stop taking the steroids .
Your condition will improve if there is no acidity or reflux of acid from stomach in food pipe.
In doubt do reply