What's the possibility that a boy's head left a dent in my gles case?

I'm nearsighted and I have gles and I keep them in a case-Like one of the hard ones. And today a 14 y/o boy really pi$$ed me off, so I hit his head really hard with my gles case (I wasn't teasing him or anything; I put some power into the swing and it made a solid thunk) and there's a little dent towards the end, I think where I hit him. Could his head have left a dent or was it something else??