Hi Friend I am Dr Bilal and I am an Ophthalmologist
Welcome to Health Care Magic and thanks for writing to us .
I would like to answer your question and your satisfaction is my goal .
As your son has suffered from black eye and now his left eye is red and swollen and he is experiencing
headaches as well , I would suggest you to get him examined by an eye doctor as soon as possible as there could be
traumatic uveitis , iritis ,
hyphema (collection of blood in the anterior chamber ) , orbital floor
fracture etc . But for his definitive diagnosis and treatment , you need to visit your eye doctor soon . Please do not take it lightly as there could be more serious complications . Meanwhile you can give him pain killer medicine in tablet/syrup form like
Ibuprofen as per his age ( as you have not mentioned his age ) and apply ice packs over left eye .
I hope you will find my answer helpful .
Wish your son a very speedy recovery .
Goold luck .
Best regards .