I have a bruise from about a month ago and the swelling is not gone yet..?

I woke up one morning to a giant bruise directly above my ankle. This is not uncommon for me, I tend to hit things regularly and I bruise easily.. but the discoloration of the bruise is gone, yet there is still a rather large hard spot where the bruise was. It feels like a lump or a knot in the muscle. Does anyone know what the actual cause of this may be? Should I seek my doctor for further help?