The strange thing is that Jabba had two seams on his “tail” section, one which was much larger and hidden without having to add a scar. Though the tail had to move a lot more, and they might have found the scar to simply be a quicker and easier solution while also adding some implied backstory to his life as a crime boss (similar to his tattoo).

As for the story of Fisher puncturing the tail and stepping on the tail puppeteer, the guy who actually sat inside the tail, Mike Edmonds, has made it quite clear that he has no memory of her stepping on his head, so it’s most likely just a rumor (supposedly started by Stuart Freeborn btw). It’s talked about in this video: https://vimeo.com/118751672