I have one caused by Oxypowder . I wasn't constipated or straining but whatever Oxypowder melted inside me caused some burning stools and the burn caused it. I kept passisng burning liquid over and over again. Coated the area with vaseline and everything and it didn't help.
Months later..I'm still regular, still cleanse with other things...never strain..but still have a hard marble down there.
Besides being annoying and gross..and having to circle it and wipe it trying to get it clean after having a bm..It's ugly enough to be embarrassing if I ever have sex again. It's more towards the front..easily seen. :(
I regularly use witch hazel..but the only thing that does is keep it from getting irritated.