About 4/5 days ago I noticed DD3 had a small red mark on her cheek. I thought her sisters had been playing a bit too rough with her and thought nothing of it, then DH said that it was there when he took her out of her car seat (she had been asleep when the mark appeared). Then the next day a white line appeared through it like it had been recently scratched although it hadn't. This white disappeared and it was a pinky red mark again. Then yesterday a red line appeared like a scratch but again she hadn't been scratched. A few hours later I felt it and a lump had appeared underneath it. You can't feel this lump from the inside of her mouth but can if you run your finger down her cheek. Now the mark is fading in colour and size but it leaving this lump behind.
I was wondering what on earth it could be. A neighbout said a sting but there's no insects etc around and they way it's changed makes me think not but I have no ideas on what it could be. Am I being a neurotic mother? Or would others be a little worried? TIA