What a start

It snowed this morning, a little, but it was nice to watch. I just came home from work after a very long day. It didn't start very well. The streets were frosty and icy and on my way to the bus station I slipped and fell down a flight of stairs. I'm fine. Only my knees got badly bruised. Now that I'm home I noticed rashes - redness - on my lower legs. I didn't see them last night or this morning. It doesn't even itch. What could it be?