"at least I'm creative unlike you" and this hurt me deeply because the last couple of months I've felt pretty down about me not being able to be very artistic.

Did you tell your bf about how low you felt about this BEFORE he made the comment?

"meh, at least I don't keep everything inside and let it rot until I create a bigger problem" because I can't openly talk about my problems easily.

Yes, another insensitive comment, but true in itself, or would you disagree?

But the fact that he hurts me deliberately to get even is something I can't stop thinking about.

Yeah, that's not okay. He's apparently frustrated about your lack of communication and instead of talking it through with you, he's passive aggressive about it and hurts you deliberately. Not okay.

What can I do or tell that isn't 'dumping him right now'?

Sit him down and ask him why he deliberately needs to get back at you. Try finding a way to communicate more openly with each other. Work on yourself.

And yeah, maybe stop "joking" for a while.