Dream has freckles, so does nightmare. But nighmare started covering them up after being corrupted.
As a child nightmare used to wear his hair in braids. They were braided by Dream and adorned with light cyan ribbons. Dream used to have his hair down.
After corruption Nightmare stopped wearing his hair in braids. Later after escaping the rock prison Dream still had his hair down, but eventually started doing his hair like in the drawing. And also using light cyan ribbons.