It's most likely piles or an anal fissure (same thing, I think) If it hurts you can use Anusol or Preperation H. If you've got moist wipes they're easier on your bum than dry paper, but not a necessity. Stool softener can help make going easier, so that its easier for your bum to heal but ask your doctor about this first before taking any. It'll heal on its own, but will likely keep coming back. I get it fairly regularly due to constipation.