Is Painful, Sore, Dark Burise On Thigh After Being Hit Serious?

I am 31 years old, I am 5ft 8 inchs, weight 11.5 stones and have no medical history. I bang my thigh on the corner of my table 8 months ago and although the purple parts of the bruise have faded, I still have a dark bruise which is still sore when touched.
Please let ne knoe what it is or what I should do