strawberry mark

Another mole the size of a farthing on her thigh and something purplish on her calf—a strawberry mark, a scar.

He had a strawberry mark on his forehead.

I recognised it by the strawberry mark in Cap.

His mother said, ‘Yes, our son has a strawberry mark under his right arm.’

Really, your story runs like a melodrama, where the hero turns out to be a duke and his mother knows the strawberry mark on his arm.