I had my last session of IPL in my bikini line 4 months ago. But I hate the shape, will my hair grow back again?

Thank you for your question ariaaaa. I understand your concern.
IPL is a great treatment for facial rejuvenation. IPL can also be used for permanent hair reduction. It is important to understand the permanent effects before starting a treatment. Usually 6-8 treatments are required for full results. Please consult with a doctor for specific recommendations. Good luck!

The laser or IPL kills the follicle and that same hair will not grow back. Over time, your body does recruit new terminal hairs, so a few random ones will show up sparsely in the bare areas, but these will be few and far between. 

After two months it is doubtful that the hair will grow back in the area that is bare because the IPL did what it was supposed to do. The areas with remaining hair need to be treated again to destroy the hair follicle and prevent the regrowth of hair. It's the same answer with the fine hair that remains as long as the hairs themselves are darker in color. Make certain you do not want hair regrowth in the areas to be treated because hair growth will not take place once the hair follicles are destroyed with IPL. Good luck!

Unfortunately the hairs that have been permanently affected (meaning the follicle/bulb have been destroyed) are incapable of growing hairs anymore. So your patchy areas this long after treatment will continue to remain that way. Those hairs don't have a bulb for the hair to grow from anymore. "This answer has been solicited without seeing this patient and cannot be held as true medical advice, but only opinion. Seek in-person treatment with a trained medical professional for appropriate care."