When does hair begin to grow back?

It is important to bear in mind that each hair has its own independent growth cycle, i.e. each follicle has its own hair cycle, meaning that hair does not grow and fall out at the same time.
The hair growth cycle is divided into 3 phases:
ANAGEN PHASE: This is the hair growth phase that lasts between 1-3 years. This is the regenerating and growth period during which each hair grows between 1-2cm a month.
CATAGEN PHASE: This is a short transitional phase that lasts approximately 3 months during which hair stops growing before reaching the final phase
TELOGEN PHASE: Hair stops growing even though it is still attached to the follicle. This phase lasts three months until the hair falls out by itself or if it is removed by hair brushing, styling or washing.