Hi..
Welcome  to  HEALTHCARE  MAGIC  ..
I  have  gone  through  your  query  and  can  understand  your  concerns. ..
As per your complain it seems that there is 
soft tissue injury secondary to trauma leading to swelling in the area of the temple and the cheek..
There is accumulation of inflammatory exudate, cells as well as inflamed muscle fibers secondary to injury..
Pain in jaw can be due to soft tissue injury while there is also a possibility that he has bony 
fracture at the jaw joint or the jaw or thee can also be dislocation of the jaw causing pain..
I would suggest you to consult an Oral Surgeon and get evaluated and also get a full mouth x Ray known as 
ORTHOPANTOMOGRAM or OPG done to rule out for any fractures or dislocated jaw so that treatment can be planned accordingly..
As of now do cool compresses over the jaw..
Take anti-inflammatory painkillers like 
Ibuprofen..
Take 
soft diet and more of fluids..
Avoid excessive mouth opening..
Hope this information helps..
Thanks and regards.
Dr.Honey Nandwani Arora.