HELP! Sore on back of foot that won't heal... what should I do? What could be wrong?

I'm 16-years-old and a sprinter. I do short distances because I have asthma. One night I was wearing my brand new flats and it was freezing outside... I got a tad of hypothermia and I couldn't feel my feet but my right heal stung. When my friend got me into a warm place, I tried to take off my shoe and noticed the place that the skin had been rubbed off on my heal (about the diameter of a pencil eraser) it was raw, so I thought nothing of it since I get irritated skin pretty often. I had track conditioning the next day and before that I had P.E, during which I noticed that I couldn't stand to have a back on my shoe touching my sore. I had socks on and I didn't have a bandage, so I went to conditioning and just ran with the back of my sneaker smushed down on the right side. Running that day opened the sore and made it ooze and bleed, I put band-aids, gauze, neosporin, bactrium, peroxide, etc on the wound but it won't heal! It's been over a week, almost 2, and the sore hasn't healed!

You have a blister that you have rubbed raw and it needs to heal. For this, leave all the stuff off whenever you are home and leave it open to the air. When you need to put on shoes and socks, put only a bandaid over the site. It is too early for it to be healed. Deeper wounds take longer to heal and a blister is a deeper wound.