The term 'become rough' can be expressed in two words: 'CHAP' and 'COARSEN'. The word 'CHAP' is a verb meaning to become cracked or fissured, usually due to exposure to the elements. It is also used to describe a person's skin becoming dry and cracked. The word 'COARSEN' is a verb meaning to make or become rough or harsh. It is often used to describe a change in texture or quality, such as when a material becomes rougher or harsher. Together, these two words describe the process of something becoming rough.