Dog bump
Maltese dog
Female
12 years old / 10lbs
She has been spayed
South carolina
She had a cytopoint injection on Saturday for allergies. I noticed this on the very top.of her hind leg today. It doesn't seem to bother her but I am wondering what is it. It seems to be purplish on top and a very small hole. There is a small hard knot. She is in an inside dog .