They bite people at night, when they are asleep. Once they have finished feeding, the bugs will crawl off and go back to their dens. Most bedbug bites feel mild at first, but can develop into itchy welts. There is also a possibility of infection that typically is a result of scratching these welts. Bedbug bites may occur anywhere on the body. Flea bites do not usually have a red center. People mistakenly believe that itching and welts are caused by other pests, such as mosquitoes.