I messed up, can you help me fix it at all with her?

Well what you should do is hit her up. Don't mention the incident unless she brings it up. You never know whether or not she forgot about it. & if she does bring it up say something like you didn't really know what to say or because you looked at her and she knew you were looking, that you expected she was going to say hi. & when she didn't you thought she didn't really want to talk to you, so you kept going. & end it with a joke like at least i said hi this time, im making an improvement. I know it sounds cheesy but that's what a girl needs sometimes. Im a girl who has a lot of guy friends and constantly i say things that make them mad or wanna puke lol . Depending on which of the friends im talking to my apology is turned to fit them.. I know that seems irrelevant but it's not. If the girl your talking to is bubbly then be fun about it, but didn't make as though you're not taking her seriously. If the girl is more down to earth you probably should make your answer more down to earth and reasonable. I hope this works :D