? Blood in needle after injection

Hey! We haven't been on for while - just coasting along while managing other pets who are sicker...
So we've been using Lantus for over a year and are very comfortable with injections at this point, but for the first time I just noticed a slight pink tinge to the little bit of fluid left in the needle after I gave Rascal her injection.
I'm assuming I just nicked a tiny vessel or something, but is there any cause for concern? Could I have injected into a vessel? Has this happened to any of you?
I will test more in the next few hours just in case.
Thank you!

 

It's been 45 minutes and the insulin hasn't even taken effect yet. I'm thinking if it had gone directly in a vessel she'd be plummeting by now. We are probably ok.

 

I always check to see if that last tiny drop came out too. Sometimes it has a pinkish/whitish translucency to it, I always assumed it was just the normal body fluids.

ETA: I find if I hold pressure on the plunger until the needle is removed, it's more likely to deposit that last drop. I also let go of the tent a second before removing the needle, so the skin can relax first.