I was told I have a barrel toenail. It is very painful. Wearing shoes is very difficult. What is it, and what can I do to aleviate the pain?

I am sorry but I am not quite sure what a barrel toenail is? Could you describe what is going on with the toenail ie. thick, red, irritated etc. just to help me understand what is going on with it. Barrel toenail is a term I have never heard used and I could not access any information using that description.