There are a few reasons why your leg hair might grow back so quickly after shaving. For one, hair grows in cycles, and you may just be at the beginning of a new growth cycle. Additionally, shaving only cuts the hair at the surface, which means that the hair follicle remains intact deep below skin level. When the hair starts to grow back, it does so from the follicle, resulting in a sharp point that can feel prickly. Finally, everyone's individual hair growth rate is different, so some people simply have faster-growing hair than others. If you're unhappy with how quickly your leg hair grows back after shaving, consider trying other methods of hair removal, such as waxing or epilating.