My daughter has this red mark. I believe it's called a hematoma? anyways, it used to be flat and now…

My son had one on his chest and it completely faded by age 2

This is by no means common but my daughter had something similar on her neck that the doctors didn't seem too concerned about so I didn't either, but one day it bubbled and turned black so I brought her to a dermatologist and it ended up being skin cancer. It is very rare but I'd say just keep an eye on it and watch for changes.

My son has 2 very large ones on his chest that went from flat to raised. They are not a concern.

Hemangioma i believe. My daughter has one on the inside of her wrist. Never raised or bubbled and at 14 months old it's almost completely gone. Would've made a cool birthmark though.

Yeah my son had a "stork bite" on the back of his neck, that went away by 2. But this seems different to me

My daughter has one, it was small like that and got a bit larger. We call it her raspberry. It was the color of a raspberry and about an inch and a half. It has gotten smaller and is now a light pinkish color. She is 9 now. I'm assuming it will be completely gone in a few more years.

My daughter was born with a hemangioma on her face under her eye. It started out as just a little dot and grew quite large. It also was raised. She was on medicine for a while since hers was right under her eye. She’s 5 now and it’s still not gone all the way, but it isn’t raised. It’s a light pink spot. The doctors told me they have three stages. The growing stage, the plateau, and the going away stage.