Originally Posted by thomas20
I believe it is the parotid gland that you are seeing, and some horses will get swelling there that doesn't seem to go away. If it comes and goes it may be a sign of a mild allergic reaction.
If it could be due to something she's allergic too, when my friend d-wormed her last, she said she switched her d-wormer.
She used to use Horse Health d-wormer, but the local store no longer sells that so instead she bought a different d-wormer. I think she said it was Quest, and in a green box. I don't think she has ever used this before.