5 months post op TT now and I noticed a dry, dark line on top of my belly button, what is this and will it go away? (photos)

I am very happy with the results of my TT and lipo. Recently about a month ago I noticed a dry area forming on the top left of my belly button and it has continued to rise up lengthening. The skin feels different than the other skin and is rough and darker. What could this be and is it going to go away eventually? Thanks!