Well arent I stupid?

For tea I was chopping an onion with a food slicer one of those V shape violently sharp things.. I confess without the guard, why? well getting started is often a problem so I got it going and all was well it looked like an inch left and it was set to 0.75mm slices.. only obviously it was a slight illusion with the root and well slice "oops" .. its more like 2mm slices and there was a rather impressive lump of the end of my finger ..

It didnt bleed that much but now I have a rather flat spot on my finger.. I am such a moron