A strange bump on my leg?

I have had this bump for about a year. It was painless and reddish. Then it started to itch a couple of months ago and began drying out. I thought it may be a wart so I put apple cider vinegar on it daily for like a week. Then a month or two later the surface turned whitish and peeled away. Now the wound is raw. I put apple cider vinegar on it again in case it was a wart to hit the root with it. Now around it is a little swollen and the border of it is black and the center is yellow and is slightly secreting some sort of liquid. I put a band aid on it and when I took the band aid off there was a yellowish sectetion. I also a couple of months ago started getting a couple of smaller bumps on my legs that are painless and resemble this one. What could it be?