How to Treat Burn Discolorations from IPL Hair Removal Treatment on Bikini Area?

You may need to see your Dermatologist for an evaluation.  If the spots are pigment forming, we usually use a mild steroid like 1% hydrocortisone for a week, off a week, on a week and off a week, and use a bleach cream after all is healed.   For your skin, a 1064 Yag or 810 diode are the safest lasers to use.  Avoid IPL devices.

Before you spend $$ on peels or IPL, try these topicals.
This is called post-inflammatory hyperpigmentation (PIH). 
I recommend Melarase AM and Melarase PM creams from Kare Skin as well as a broad spectrum sunblock like Spectrase. Bothe are from Kare Skin. Scler-x post inflammatory hyperigmentation relief complex is a great supplement to take as well. See link below. 
Spectrase is a wide spectrum sunblock SPF 50+that is also recommended to prevent ongoing inflammation. 

Laser hair removal can cause burns on the skin for various reasons. Fortunately they are usually superficial and rarely cause scarring. Hydroquinone cream may help if there is increased pigmentation that persists. Be careful to use a good sunscreen to protect the new skin from developing excess pigmentation.