What should I do, should I really tell on him or am I over reacting?

This boy in my year 3rd/10th, we are both 14 I'm a girl by the way:)! Okay so this boy has once smacked me over the head to hard my neck had pains for days and today he swung something into my eye and for a while my vision went blurry, only my friends know about this, my mum or dad don't my auntie only knows about the first thing. This is happening in school, he also shouts a whole load of verbal abuse at people, and weird stuff like my friend has a baby sister who's 3 weeks and he's like Ooooh Mia;)! The babys name, and we are just like Ew you creep, do what should I do? This may sound stupid but I'm quite scared to tell someone incase he does something worse:/? I'm starting to get really worried and it doesn't help my eyes in pain:/!