Understanding a Deep Bruise: What to Expect & When to Worry

Question
Hi, Just want some reassurance.
I pinched my finger in a bi-fold door last weekend. The general area turned a little red initially but the main area turned BLACK very quickly. That area is still black and feels hard.  Is this just a normal response to a hard pinch?
Thanks.

Answer
yes, you bled into the layers of skin and the blood is trapped in there.... it will take weeks for this to slowly open, peel off then heal in from the sides... you are talking about the skin, not under the nail.... under the nail blood should be drained thru the nail but the skin blood blisters should just be left alone...