Not the best picture quality but this appeared on my daughters thigh during the night. She swells up…

Not the best picture quality but this appeared on my daughters thigh during the night. She swells up when a mosquito bites, but she was never bitten by a mosquito. Since the picture was taken these have grown and become more swollen and red. There's small red scratch looking marks in the middle, too, but the camera never picked those up. Any idea what it might be and how to help the pain? She keeps saying Owwy and grabbing at it.