lump under skin on ear

Question
I have a rat terrier, he is 5 years old.
We recently took him on a trip to Dallas. I had noticed a small swelling on his ear, which has gotton worse over the past week. It is roughly the size of a small grape. I thought maybe it was a bug bite he may have gotton at one of the rest stops, which may have gotton infected.
However, since it isn't getting much better, I am wondering if it is something worse.
Thanks,
Mike Berwager

Answer
He really needs to have the swelling examined by a veterinarian to determine exactly what the problem is.  If it was a bug bite, it should have gotten better by now.  You can give him Benadryl 1 mg per pound of weight three times a day until you get him to the vet.