Help me out

Ok ladies and gents, I have an issue. I’m a nurse. A surgical nurse. I have a very accident prone clumsy teenage stepdaughter who gets hurt, like today at school and it’s a banged up bruised knee. My husband and I get home from work and she’s sitting on the couch bawling her eyes out saying that her knee hurts. Which I’m sure it does, she skinned it pretty good. I examine her, it’s not broke, doesn’t appear to be sprained or strained and has no swelling. The daughter is still crying telling me that it’s swelling that her knees look different and we should be taking her to the hospital. Now I realize because of my profession I’m more likely to tell someone to rub some dirt in it and walk it off. I’m not very good with the over dramatic cry wolf thing, I see it way to often, (especially from said child) and have gotten kind of cold to it. I’ve spent hours in an ER before for a bruise. Not to mention she seems to be getting around on it just fine now. Am I being a terrible parent for not taking her to the er? Mind you if I thought it was an actual emergency I’d already be there...