Should I apologise?

Just somebody in college... an aquaintance, not exactly real friends... haven't said hi to him for a few months even when face to face with him because of some awkward stuff in school, but those akward things've been resolved now after a trouble maker dropped out of my college. I want to say hi now. Probably he doesn't care if I do, but it breaks my heart to give somebody the cold shoulder on purpose. Should I apologise to him for being unfriendly\rude or etc? Will he think that I'm daft or strange if I apologise? Any suggestion how to apologise? It will be strange if I suddenly start saying hi again won't it so I should apologise first? It's complicated ... we aren't very good friends or hangout mates, just cl mates and acquaintances