hi, i got my cat spayed two weeks back, and she has developed this swelling behind her skin sutures one week after the surgery. there’s no discolouration, or tenderness, or drainage of any kind from the sutures. the swelling itself feels firm, and soft tissue-esque. my cat herself doesn’t show any signs of discomfort/pain either. no loss of appetite, no diarrhoea or change in bowel movements, no change in behaviour, no lethargy, etc.
this is my first pet, so i don’t have any experience in the post-op recovery of cats, and what is considered normal or not. also i live in a super remote area, and the vets in my town are more experienced in cattle, so taking her to them was of no help. they think it’s an infection or hernia. i don’t think it’s either because there are literally no signs of infection, the wound is absolutely clean, and it’s not hernia because it’s doesn’t reduce (and if it were at a strangulated/irreducable stage, there are no systemic signs to support that diagnosis).
the hospital where i got her spayed at is in a different city, and i talked to the surgeon who performed the surgery on the phone, and going by the pictures, he thinks it’s probably a seroma. he absolutely shot down the hernia possibility, because he says they put uninterrupted sutures, so the chances of hernia are very rare.
my local vet has put her on a ceftriaxone plus dexamethasone (intramuscular) regimen, for 4 days to see if the swelling improves or not. but i am not super confident about their judgement since they are not experienced in cat physiology, at all. they didn’t even consider it could be a seroma, i had to explain it to them. i just need to know what are the chances of it being something serious, because if it’s only a seroma, or a reaction to the internal sutures getting dissolved, i’d rather not have her uselessly medicated.

so, tl;dr how does a seroma swelling feel like? and how do you differentiate between a swelling due to seroma, or because of the body’s reaction to internal sutures healing?