Im not sure but it seems that the pitcher was "bent" so that it sort of cracked on one side. I dont know if you understand what im saying but I will post a pic later of it.
Ohhhhhh.... did it arrive bent like that? If it did not, do you know if it was bent because it was bumped accidentally or if it kind of grew funky. If it grew all funky, keep a close eye out for aphids. What can happen with sarrs is when new growth starts to pop out, aphids attack the new growth. By the time it reaches a respectable size they usually lose interest in that leaf (pitcher) and move on to the next one. By this time, the damage has been done and the leaf ends up growing kind of mutated like. My guess is the pitcher was bumped but its hard for me to see.
It arrived like this but I think I did some further damage when I inspected it. Do I let it grow or cut it off?
My personal style of doing stuff, I would let the leaves grow out for a bit then cut it off once it starts to annoy me. I am not sure it really makes a big difference. If you cut it off, one could argue more light can reach the crown as that leaf won't he blocking the light. But then again if the leaf is not totally mangled it is still photosynthesizing which provides energy to the plant. I am not 100% sure with sarracenias but with most other plants, cutting leaves off can encourage new growth. I would tend to suspect this is true for sarracenias but don't quote me on that. If it started to turn brown and nasty I would probably let the leaf die off then cut it.
Oh, another thought occured to me earlier. Aphid damage, when I have had to deal with it, tends to be most noticeable around the top of the pitcher. In hindsight, I am not sure why I looked at your pitcher and started thinking aphids. Aphid damage looks less like the leaf has been bumped or bent and more like weird mutated growth.