I am training for my first half marathon. I've got 4 weeks to go and have just completed a 16km run. New trainers (my old ones were three years old and I could feel the pavement under my feet!). Anyway I had a small blister on the bottom of my foot which I covered with a blister plaster before I went out. I could feel it hurting but carried on (I'm a wally I know). Now I have a giant blister plaster sized blister on the side of my foot. It's agony but my main concern is that I need to keep running. What can I do to speed up the healing process?