Eyelashes that have been pulled out often grow back in approximately two months, depending on the extent of any damage to the hair follicle. If the lashes have been pulled frequently over time, or if damage to the follicle exists, the process can take longer.
The hair follicle must complete three phases before the eyelash is fully re-grown. These are the growth phase, the transition phase and the resting phase. If a lash is pulled during the transition phase, regeneration of the lash will take longer. The delay occurs because transition must be completed before the follicle enters the rest phase, when the eyelash falls out and the cycle starts again. However, if constant pulling of the eyelashes results in extensive damage to the hair follicle, the lash may not be able to regenerate.