Hope you sterilized the knife and used hydrogen peroxide afterwards.
I feel your pain...
My worst cut came when stepping from a boat onto a floating dock in Hawaii, and I slipped and cut the top of my foot on an oyster - took forever for that sucker to heal.
I also got a coral cut on one of my feet once, and treated it myself - the coral was embedded in my skin and kept growing...the Doc eventually had to cut my foot open again and dig out the coral.
ADG