This kind of thing happened to my Aunt once. The biggest concerns are: how deep? have you had your tetnis shòt within the last ten years, and was the needle rusty?
Chances are, you'll be just fine. I image it didn't cut too deep if you didn't scream enough to wake anyone.

うわぁ;みてるだけでいたくなるよ。
きずがはやくなおりますように…。