A sharp razor blade makes an even cut without leaving foreign particles in the wound. And although such a cut causes pain, usually these discomfort disappears after a few minutes.
By contrast, a sheet of paper, in addition to the cut, does other minor damage with the help of microscopic fibers in its structure.
Also, particles of these fibers and other foreign materials remain in the wound after paper cuts, which continuously stimulate pain receptors in the skin at the edges of the wound. In turn, a large number of receptors increases sensitivity, and a person experiences pain even with minor injuries.
It’s worth noting that since the cut bleeds only slightly or not at all, the blood does not “wash out” foreign objects from the wound, and new irritants get in. All this causes a person prolonged pain compared with small bleeding wounds in other parts of the body.