I have a white Persian who is groomed at home for a majority of the time, but every few months is taken to a vet to be professionally groomed while sedated for really deep knots (she’s so panic ridden/violent when scared it has to be a sedated groom)

Day 1: She was sedated and groomed and all went well. They grabbed some labs while she was sedated, and told us that she was given a fluid-bump before leaving. Bringing her home, there was no sign of injury anywhere.

Day 2: The next day, we noticed a slight bruise where they said the fluid bump would be (in-between her shoulders) but didn’t stress too much about it.

Day 3: Her bruise was darker this morning, within 1 hour it got even darker, hours later it became an open wound.

Her scratching an irritated spot makes sense but we’re also nervous that she could be having an adverse reaction to whatever the fluid bump was. What does Reddit think is happening, and what should we do?