Recently went to the hospital to give blood samples. Here's a tiny bit of background.

The nurse was lovely and very experienced, but I found it incredibly stingy and felt extreme discomfort (it was like the needle touched a tendon or ligament).

I've had blood taken in the past and have never had any issues. I usually don't even feel anything and I literally wouldn't even know where the needle entered the skin - there was usually zero pain/discomfort and absolutely no dot where the needle pieced the skin or any bruising at all.

Anyway, after I saw the nurse, later in the day and for about two days after, the area was very bruised, like a 1.5-2inch wide dark purple bruise around where the needle entered.

This was weeks ago and after the bruise healed I've had zero issues with that area on my arm.

My main question is - Why did this hurt so much and cause bruising when every other time it's been a very smooth and low-pain experience that doesn't result in any bruising?

Thanks a lot!