Quoting Mylittleone's (B.B.M):" It's scar tissue I have a hard spot where I was stitched had it checked out and they said it was the ... [snip!] ... you have more blood flow down there and your vaginal walls can swell which push that part out more and makes it feel worse."
I am 8 weeks pp and it feels bigger than ever so I guess it could be scar tissue, but that doesn't explain what it was initially when it started out as a rough spot. Now when I walk I feel like I can feel it. I always forgot to mention it to my Dr when I was pregnant but I would think if I had warts he would tell me.