My gf and I got into an argument and I ended up having to restrain her;she says I hurt her.How do I make it up?

That's hot, lol. Anyway, talk to her. Tell her everything you typed here and just explain your actions. Tell her she pissed you off and you got upset [a normal reaction, btw]. SHE should apologize. You did nothing wrong [if you really DIDN'T flirt with that girl] and clear the air over that whole little argument. If she really cares, she'll apologize and [you don't have to] but if you feel the need to, you can apologize as well. You have to be honest, that's the quickest way to getting back to normal.