What Is The Treatment For Bruise In The Forehead Of A Child?

my son 18 mnth old and he sleeps n a pack n play but its not by the wall when i put him to bed he was find n the middle of the night i went to check on him and there brueses on his for head theres nothing n his bed to hurt my kid today he been really fussy.... he has a doctor appt tomorrow is there anything i can do for him for tonight? should i bring to the Er?