This is works great for me: Wipe as well as you possibly can after each BM. Then, use baby wipes (the only ones I've found that don't burn is Parent's Choice in the baby section at Walmart). If you're really raw, even these will burn, but suck it up so you can get clean, then use a product called, Proshield Plus. You may have to special order it from Walgreens. It's a little expensive but lasts a long time.
If this doesn't work, you may have a yeast infection in the anal area and using a product called "Zeasorb", works very quickly (like one or two applications) to clear things up. This stuff is also expensive, but works really well and lasts a long time. Used to find it at Walmart in the foot fungus section, but couldn't find it there the last time I needed it. Found it at Walgreen's in the yeast infection section.
I hope this helps.