I have a bruise on my hand , that started bluish green and is turning purplish and redl. Except there is a firm, white bump in the middle, that is the only part that hurts, not the bruise part.I do not remember hitting my hand that hard, so I worry it is a spider bite . I also got a cold around the same time it appeared. Regular symptoms; sneezing , chills, sore throat and sinuses draining. That was last weekend, so exactly a week ago. The bump is firmer and more visible, the cold is almost gone, so what do you think this is?