Ask the Swan Specialist
Date: 25 August 2017
You need to get her to a licensed veterinarian ASAP. This small lump under the chin could be a puncture wound with something embedded, i.e., pine needle, stick, etc., causing an infection that could be life threatening if she goes septic.
It could also be a tumor and is best left to a veterinarian to exam and biopsy if needed. Much better to be safe and treated quickly. The Regal Swan