swollen cheek

my puppies cheek has swollen to about the size of a golf ball, and is very hard. he seems to be ok, still eating and drinking. his skin is actually sagging real bad on the size of the lump. Is it just a sting, something i should take to the vet asap or is it something i can wait till monday. He has a check up then.

[Jim Humphries, B.S., D.V.M.]

I would suggest an exam and treatment today if possible.  If this were an infection and it became much worse tonight, then you have emergency fees tomorrow.  

Can be any number of things.  The sagging is due to the extra weight of the swollen tissue.  The hardness means severe inflammation.  Could be anything from a thorn, scratch, insect sting or even an infected tooth.  

If it were my dog I would not wait!