What Causes Difficulty In Swallowing And Swelling In The Jawline?

We have a house guest who has symptoms including difficulty swallowing, ear ache and swelling near his jawline. This is of recent onset- he felt fine most of the day. He has no food allergies THAT HE IS AWARE OF. I am certainly not an MD but I have thought about the following as possible reasons: Blocked salivary glands, ear infection, mumps, a bacterial infection. I does not seem to be an allergic response for some reasons, but of course it could be. I have offered to take him to the ER but so far he wants to put some ice on his jaw and wait to see if he feels better soon. My question is basically: How can I help him to rule out or pinpoint the most probable cause?