So this may be from the moisture or fecal incontinence. I would guess due to the clothing we wear in this time of year, it sounds plausible for it, however, the aggressive wiping may be another too.
I thought about fissures but the doc said there was no sign or abrasions or cuts he didnt see anything.
I think this is a case of Pruritus Ani or Anal itching. It is common for folks to experience this matter. It happens when there is moisture, fecal incontinence, and sometimes anal fissures. Rubbing or too much friction from toilet paper may be the reason for the streaks of light blood appearing on it.