Shot?

2 Days ago my 1 year old got her shots and one of them was for the flu and I'm pretty sure that is the one that's doing this, it still looks pretty red around it and there's this weird patchy thing happening right next to it, has anyone had this happen and knows why it's like that? Could she be allergic to something in it or is it normal for this to happen around a shot like some sort of bruising? Is this something I should take her to get checked out?

Edit: it also feels pretty warm to the touch but I'm gonna go ahead and call her doctor thank you guys so much for responding