Yeah, you can just use a slin pin with hCG. You're going to just have to overcome your fear and stick yourself. The first time is always nervous. I remember when I first injected AAS into my delts and I pulled the syringe out and blood was literally squirting out and I was totally freaked.
But, with stuff like hCG in a slin pin you're just going to feel a little pinch and pull the plunger back to aspirate, then inject it. Simple as pie.