Eyelashes will grow back after they are cut short. Like hair, eyelashes are in a constant state of metabolism and renewal. The average lifespan of eyelashes is usually 3-5 months. That is, eyelashes that are shed, plucked or cut will usually grow back after a week, growing about 1-2mm per week and reaching their original length in about 10 weeks. Clinically, many patients will usually go back to the hospital to have their eyelashes removed 2-3 months after they have been plucked, because the rate of eyelash growth dictates that this phenomenon occurs. After the eyelashes have grown to their original length, they usually persist for 5 months, falling off and then recirculating, constantly renewing and metabolizing, so as long as the conjunctival sac is not destroyed, the eyelashes will continue to renew and grow.