Just won millions in the lottery? Congratulations! Here's what to do — and more importantly, not to do — to avoid making some very big mistakes.

At least one Mega Millions player has plenty of dough to ring in the New Year after drawing the winning number. After three months without anyone winning the top prize in the lottery, a ticket worth an estimated $1.22 billion was sold in California for the drawing Friday night, according to the Mega Millions website.

Find out the details about the $1.22 billion Mega Millions jackpot won on Friday.