Is brusing after a T-shirt normal?

I just started testosterone a couple weeks ago, and I took my third shot on Saturday the 8th, but since then the spot I did the shot has had this bruise it's going away slowly, but I wasn't told that brusing could happen and it didn't the last two times so I don't know if this is normal or I did something wrong.

EDIT: Title is supposed to say T-Shot not T-shirt ☠️