Get Your Dog Care Questions Answered by Experts
I am sorry to hear you are worried about Bella. My name is Rebecca. I am a veterinarian and will do my best to help.
How long ago did this sneezing and runny nose start?
Is she eating or drinking normally?
Did the opossum bite her? I doubt she would be infected from the opossum until it bite her. If she did get an infection from it, I would expect her to have a fever; can you take her temp with a thermometer?
A clear discharge, and sneezing, may be due to allergies. You could try nose drops for children such as Little Noses, and/or Benadryl. The dose of Benadryl is 1 mg per pound of body weight, so a 50 pound dog would take 50 mg, 2 to 3 times daily.
If she is eating normally then this is probably not too serious. Let me know if you can take her temp, and what other questions you have.
I hope you were able to see what I wrote. How is she today? Was this helpful; can I answer anything else?