External and internal hemorrhoids are essentially the same thing – swollen veins. External hemorrhoids are hemorrhoids that have prolapsed and are on the outside of the anus. They are swollen and inflamed and visible to the naked eye. People who have external hemorrhoids suffer enormously, because the skin in that place is sensitive.
In contrast, internal hemorrhoids cannot be seen with the naked eye because they are inside the anal canal. Internal hemorrhoids are usually not as painful.