we went along a normal day, nothing different happened, went to the mall, late at night around 8:30 my brother about 10 yrs notices a darker colour around his Left eye. the colour is kinda purple and red mixed, looks like very tiny freckles. it causes him no discomfort,no pain, and he has no recollection of being hit, i don't think he was hit as i am the one usually doing the hitting,(big brother)

any ideas?