When you play with color yourself you run the risk of things like that happening. I hope maybe next time you will be more hesitant about doing it yourself. You can try mixing your regular everyday shampoo with baking soda to make a thicker consistancy and let it sit in your hair. That is the best stripping shampoo you can get. You were right to try and strip it out of your hair. Go to your hairstylist and have them color it back to your natural color. But depending on how much gray you have, you may have to color your hair with permenant color b/c semi permenant color is not formulated to color much gray. Although it will color some (if you have a small amount) it will fade faster than permenant b/c it doesn't sink into your cuticle as much, it just coats it. so try stripping it with baking soda and go talk to your hairstylist.