The difference is that the corneal is a cone-shaped hyperplasia of the corneal layer towards the dermis, forming a keratin peg in the middle. The surface of the wart is a loose keratin layer that is easy to peel off. After peeling off, the edges are slightly elevated, and when peeling off, many black spots or pinpoint bleeding are found. The painful condition is different from corns because the inverted cone-shaped growths of the stratum corneum have a pinprick sensation when pressed vertically downward, because the needle point is like sticking on the dermis, similar to the pinprick sensation when injecting, and there will be a pinprick pain. Hematocrit spur is a papillary hyperplasia caused by viral infection of the dermis, and there is no obvious vertical pressure pain and a painful sensation when squeezed.