What could this be!?

Shannon • Mother of 4 beautiful girls💕

My daughter has this big bump on gwen thigh/leg area where they would give shots! It doesn't look like a insect bite, it doesn't itch her, its swallon & very red, it is warm to the touch! All I can think is if it's a reaction to her shots she had last Monday.? But wouldn't that of showed up a lot sooner? It didn't show up til yesterday morning and it has got a little bigger since then.