Honestly I have never not hit the muscle so I cannot be 100% sure. However your skin/fat should only be about 3/4" deep depending on where you injected. Did you inject on the lateral side of you glute (towards your hip joint) or the medial side(toward your crack)? The lump would most likey be close to the surface...I have had small lumps in the muscle before when I injected into my biceps. I would try to put some pressure on it and try to massage it out.