No need to worry..you should try to drink ginger milk with your whiskey also taste very good. I remember when I was little, mum aunt always mixed it together and let me drink. Especially good for winter time which can keep you keep you warm and easy to fall to sleep as well. Also taste very good too.
Think milk was too hot, that's why it failed. Try pour milk back and forth 10 times after it's ready to lower the temp. I've tried this way and it works.