My little POA pony mare.

Question

I have a little POA pony, she is about 11 years old or so. I was leading her around the other day, because I do pony parties with her, and i was feeling under her head, I know all my horses are sucked in under there, but under her head it was puffy. I have no idea what could be wrong with her. It seems to have gotten bigger with time as well.

I could really use some answers.

Answer 1

does it have any puss / discharge?

this could mean it was infected