Hi, I've noticed one of my cats, Lucia, has developed a lump in the place she had her booster vaccination 9 days ago. Checking things out on the internet, I'm a bit freaked out it could be a sarcoma, especially as she had the Felv vaccination, as she's an outside cat. It's underneath the skin, seems quite firm and is about 1/2cm big. I've read it can be happen for cats to get lumps and it might be nothing to worry about, but it hasn't ever happened before, although she's only 3. I've read a lot of conflicting things about it and was just wondering if anyone had any first hand experience of this happening to their cat and wether I should take her to the vet or wait and see how it develops.
Thanks