Suggest Treatment For Pimple Like Boil On Elbow

I m a 48 year old man of Caribbean origin. I have a spot like a boil on my elbow. It has no puss in it because the tip is not white and ready to burst. If has been on my right elbow for nearly a week now and it is very painful to touch. It does feel like there is something in it. I feel it wants to burst but if I squeeze it nothing happens, it just pains me alot. It just looks like a pimple but the pain is so acute. I have tried putting a garlic on it and also tied an onion to it over night. I now have a dressing on it with Black oinment that I got from the pharmacy but it still will not go away. Please help me to get rid of it and the pain - thank you, Roger