You never mentioned how old you were. This is important when dealing with the colon. It could be, that one; you ate something like corn, peanuts or something that doesn't get totally digested. On the way out it scraped your rectum or two; when wiping you may have scratched the outside of your rectum. Enough that the skin tries to heal it self by scabbing over. This would cause intense itching in this area. Even minor scarring could occur possibly from a minor scrape from heavy tissue. Wipe with very very soft tissue. Eat a diet that it easily digestable. Stay away from foods that pass right through the intestines like corn, ruffage or peanuts etc. Drink plenty of water to flush your bowels.
Use Vaseline to keep the skin moist and to prevent it from scabbing over. If it's really painful, maybe a prep H cream could help relieve the itch and keep it moist until it heals.

What I think from your posts, is it got scraped, caused a very small tear or scratch. But the over wiping from tissue dried out the area, caused the redness and irritated it. Tissue does this. It will dry out that area very well keeping it from healing properly and causing it to scab becuase it's so dry. Thus, causing the itching.
But don't rule out hemroids. Which is anal bleeding. When you wipe if your not seeing blood on the tissue it may not be hemroids.
So, I would try a change in diet, vaseline and softer tissue and see if it improves in a week. If not, then definetly bring it up with your doc and have him take a look.
You don't have to be shy about it. That's part of life.