What is retracing? Retracing means going over ground which has already been covered until the individual reaches the point from which they started. Ex) If you go on a walk past a green, yellow, brown, and tan house, to retrace, you have to walk past the tan, brown, yellow, and green house to get back to the beginning place where you started.
Sometimes symptoms that have not manifested for months or even years will reoccur. People's first impression is that they are getting worse when they are really experiencing a retracing of the several stages through which the disease progressed in the making.
It is as simple as that.