My daughter woke up with this huge spot on her foot I don’t know what it could be. She’s been in pain and can’t move her foot what is this.. Explain this

Blood blisters strike without warning. One moment your skin looks normal, the next there’s a dark, swollen bubble that looks frighteningly serious. Panic rises. Is it dangerous? Is it cancer? Should you pop it, drain it, or rush to the ER? The truth is far more surprising—and far more reassi… Continues…