A nerve?

[Xalthus]

Today i was doing my... like 8th injection.. and my friend was doing it.. I had only 1 needle and it was 1AM so i just used the drawing needle to inject (so it kinda went in bad).. And while it was hurting and my friend was putting the needle into me, my ass kept on flinching (the muscle). And it was still kind of flinching when he was injecting.. Now what im wondering is, did i go through a nerve or something? and if so does it paralize muscle fibers? thnx let me know.