I am 12 weeks and I went to get a quick scan today. I lost one of my twins two weeks ago and the doctor wanted to check on lost baby to see if it was disappearing. He showed me the surviving baby and gave me a picture but I didn't notice until I left that it had a strange white dot surrounded by a bigger black dot in its skull. I am worried something might be wrong with this baby because I didn't see this on any ultrasound I looked up. What could this possibly be?