When you say it looks like mumps, I think of swelling on both sides of the throat directly behind and under the angle of the jaw. If this is correct, the swellings would most likely be lymph nodes, but could also be salivary glands.
Differential for swollen lymph nodes:
Inflamed or blocked salivary glands can sometimes occur in the glands under the tongue and behind the angle of the jaw. Aspirates of these glands contain saliva.
You should have the results of the cytology within a few days. I understand that the wait is very stressful.
Let me know if there are follow up questions.
The nodes tend to enlarge fairly rapidly. Development in the last 2 days does not really help limit the differential. The top of the list are generally the most common causes of swollen nodes and the last part of the list the less common causes.
Gum and tooth infection can result in swollen submandibular lymph nodes because they drain the head/mouth region and can introduce bacteria into the nodes.
My thoughts are with Rex.