Lump on left inner thigh, white head on it, hot burning sensation, growing in size. Causes and treatment?

I have a lump on my left inner thigh very close to the top of my leg. There is a little white head just to the left of the top of it which was not there initially. There is an increasing red skin around the area and it is painful, but not where the little whitehead is. There is a hot burning sensation that is constant. It has been growing since 10:30 this morning. It was not there at 9:30. It is now grown in size to approx. the size of a golf ball inbeded half way into my leg inside and out. As regards the red skin it iis now almost 1/3 the way down my leg. I have never had anything like this happen before. I am 48.