Overall, I dont think the pic is "too dark". We are not shooting flowers here. If anything, the only dark think I would lighten is the knife blade, whether it would be turning it slightly to catch some light, if you were to do a reshoot. I have shot many picks waaay darker then this.
I agree too, the wound could be a little nastier. Sometimes with the latex, and all, a toothbrush can add some nice textures, just by dabbing it around the edges. You can also "pinch" an area, to make it rise a bit.
Still a well done piece of work.