Thank You. I Have A Reddish/purple Indentation On My Left

Thank you. I have a reddish/purple indentation on my left leg near my ankle. It is surrounded by hard areas and my foot and ankle get very swollen by the end of the day. The indentation is sore to touch and aches once-in-awhile. The top of my foot hurts so badly at times that I can hardly stand it. Also, putting pressure on my foot when standing or walking is very painful. Now, my foot does not hurt all the time, but it is hurting more as he days pass. This spot started about year ago and has become worse with each day. No doctor seems to be able to tell me what the problem is. I am quite worried. It does not look good!