How to Remove Hyperpigmentation After TCA?

I would need more information to give you a definitive answer about hyperpigmentation after a TCA chemical peel. Typically, we monitor the healing process very closely as there are some products that help but they work better when started early. These usually contain ingredients like hydroquinone and tretinoin. Three months out is a little bit trickier. You should be seen by your practitioner for specific advice.

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. 

You are experiencing post inflammatory hyperpigmentation. This is not unusual following a TCA peel but can be prevented and improved if it occurs. If your face appears irritated, red and swollen then a steroid cream is the first topical treatment of choice. Since it has been 3 months for you this is unlikely. There are creams that contain hydroquinone and Kojic acid along with tretinoin. These help to block the ability of the melanocytes (the pigment producing cells) from making more pigment. It typically takes 70 - 90 days to see the full effects of this product. It is typically applied at night and you must use a sunscreen during the day. An experienced dermatologist or plastic surgeon can help you manage this problem.

Although my general recommendation is that you be evaluated by a board certified skincare specialist in person before embarking on a course of treatment, there is an over-the-counter 2% hydroquinone product called "Ambi fade cream" that likely will help. Generally speaking, prescription products are more effective (another reason to see a doctor).
Good luck.