Soak your foot in salt water, its a wonderful antibacterial and doesn't sting as much as some options.
If you don't mind the stinging I swear by Hydrogen Peroxide, the type you buy to clean contact lenses. I wash any cuts or scratches (I have two cats, scratches are not uncommon) with it and have rarely had any wound infected, those that did cleared up quickly once I noticed them and started treating them.
And if in doubt get it seen by a professional, there is no reason to take chances.