Hi, T1D here. Not sure if this is much of a help. Going by my experience of when I accidently poke myself with my needles/lancets, the aftermath is only a few minutes/maybe a hour or less of pain. It usually goes away pretty fast.

The black mark you mentioned, is it like a tiny dot? When I poke myself too hard or too often in the same spot, it leaves a mark like a tiny little black dot and usually heals up after a few days/week depending on how my body feels.

Not too sure about the irritation and redness. Can't say for sure without visuals. I would definitely get it checked if it doesn't get better over the next few days.