Does TCA Cross cause hyperpigmentation?

If it's not properly performed, it can. I recommend getting a TCA cross from a cosmetic dermatologist. Hyperpigmentation can be improved with a combination of lasers, Aerolase, microneedling/prp, skin lightening, peels, Cosmelan, and skin care. Sun protection is essential. See an expert. Best, Dr. Emer

Depends on both skin type and concentration of TCA. Your dermatologist can give you a guide line. In darker ethnic skin, PIH is seen in 100% of cases of TCA 70% or higher - video explains in the reference section. 
Acne scar revision is a sub-specialised field. For the best results, one should target the acne scar type with ideal treatments and not just one device. The web reference below will take you to a resource to help you understand acne scar revision at a specialist level. I embedded all the videos in one page to help.

 For example deep ice pick scars, and narrow box car scars can be treated with TCA CROSS peels, mixed scars, rolling, and atrophic scars treated with fractional devices such as Fraxel, fractional lasers, PRP and INFINI radiofrequency. Atrophic scars (depressions) can be treated with either fat grafts, or with HA dermal fillers. Tethered and anchored scars are best treated with surgical techniques such as subcision. Other surgical techniques that we use include punch elevation, surgical elevation, punch excision and traditional excision of focal scars.
 The majority of patients will have a collection of different scar types, and hence a tailored treatment METHOD will be best. Careful examination, especially under angled lighting with scar mapping will give you an understanding of what are the best options for your scars. In the majority of patients its finding the correct combination that give you best results, and everyone is unique! All the best,
Dr Davin Lim. Acne scar dermatologist specialist. Brisbane, Australia.