ANDY'S ANSWERS: This not likely your period starting. Wiping your bum a lot can certainly make it raw, but it's probably because your stool is too hard and dry. There are blood vessels near to the surface in your anal canal. If you are having a difficult time having a bowel movement (like being constipated) and your stool is quite hard and you have to push really hard, you might be tearing these blood vessels. Some people develop inflamed haemorrhoids, which can be quite painful as well as bleed.
The best thing to do is make sure you are eating a good diet with lots of fruit and vegetables for fibre. That will make your stool softer and easier to pass. Also, make sure you are drinking enough water and exercise. These are all things that keep your body functioning properly. Finally, make sure that you don't ignore the urge to go when it happens. You are more likely to have harder and dryer stools if you wait. It's likely not too serious, but if the bleeding continues, you should have it checked by a doctor.