Is it normal what this guy did....?

I had this girlfriend, let's call her Veronique...because that's her real name. she was a self harmer. She had really bad cuts all up her arms. It reached to the middle part of her bicep area.

Here's the cold reality of it all:
No matter how much you hope to be able to 'fix' a self harmer, no matter how much love or affection you pour into such a person, you won't ever be able to glue them back together. They just won't change their ways. They won't. Up until someday when they decide to change by themselves. But then those scars will always be there; taunting them. Mocking them. Making them feel like filth.
It takes a particularly strong willed person to never crawl back to a sharp edge again.

You can't be changed.. and that's just a pretty scary thought..

All the best to you on whichever path you choose

Sex

This sounds like a weak excuse to me -.-

He may believe that self-harming is a symptom other serious psychiatric disorders. One part of him really likes you (made him come back) and one part of him is leery of getting involved with someone he fears has psychiatric disorders (made him leave). He's torn. I'd suggest leveling with him about it, tell him you care about him and your relationship and that you won't do it again. Then don't do it again.

Maybe he had a bad experience with someone who self-harmed in his past, or it could be his own issue he is trying to get away from. Or he could simply have negative associations (stereotypes) about self-harmers embedded in his mind. He might be assuming you are an attention seeker or that you have too much baggage for him to carry (and frankly I wouldn't blame him if so, if you are just getting to know each other). The only way to know is to ask him how seeing those cuts made him feel.

If he's smart he's gonna cut ties with you all together. Nobody should put up with people who hit that stage when they're just an emotional wreck.