Some Muslims develop a permanent scar on their foreheads from bowing to Mecca. It’s called the “prayer bump”.
A prayer bump or prayer scar, also known as a zabiba/zebiba/zebibah (“raisin” in Arabic), is a mark on the forehead of some Muslims, apparently due to the friction generated by repeated contact of the forehead with the prayer mat. Islam requires its adherents to pray five times a day (known as salah), which involves kneeling on a prayer mat and touching the ground with one’s forehead. When done vigorously for extended periods of time, a prayer bump may develop. Some Muslims may consider the presence of a prayer bump to be a sign of religious dedication and piety. Some Muslims also believe that on the day of judgement, this bump will particularly fluoresce an immense white light. The bump also serves as a public demonstration of one’s piety.
The prayer bump can take the form of a discolouration of the skin, caused by repeated chafing and the build-up of callus. In extreme cases, the callus can be thick enough to create a real bump that protrudes from the forehead. They may also develop due to frequent prayer on hard surfaces such as stone floors.
Also Muslims must pray 5 times a day watch the video