Can I fill in under eye wrinkles with the TCA Cross method?

The TCA CROSS technique, which employs extremely high concentrations of trichloroacetic acid ranging from  90-100% concentrations should first and foremost not be used by untrained, non-medical personal for home use. This is unwise and potentially very dangerous, especially when used close to the eyes. Secondly, TCA CROSS was not intended for the treatment of wrinkles. It was developed for treating pit (ice pick) scars and for dilated pores. Without a photo, I can only make some general remarks about possible treatments for the under eye wrinkles that trouble you. One possible treatment would be the use of microdroplets of Botox. Another possibility, or in addition, might be the use of a filler, such as Belotero Balance. A third possibility might be a series of superficial peels, such as with full-strength glycolic acid, Jessner's Solution, or low concentration (10-15%) TCA. Less tried-and true options include fraxel lasers and radiofrequency devices, however, much of the current hype about these methods is heavily industry supported and backed more by marketing and advertising hype than hard science. You would be well advised to seek consultation and treatment by a board certified aesthetic physician with expertise in treating the under eye region, which is not area for either self-treatment or even treatment by novice physicians and medspas. Best of luck to you and Happy New Year!

Under eye wrinkles need a combination approach for improvement. I don't recommend TCA cross for this, it won't fill in a wrinkle. I also don't recommend applying TCA yourself, it needs to be applied by a professional.  I do recommend fillers, lasers and microneedling/prp. I recommend getting a formal consultation with a cosmetic dermatologist. 

TCA peel is effective in treating atrophic fine crinkly wrinkles under the eyes assuming there is no bags or fat herniation which requires surgical correction. The strength that is effective is not to be used at home or by non-MD. It will cause peeling, removal or the superficial thinned out layer of the skin and newer skin and inflammation causes more organized and thicker collagen layer underneath it. The CROSS technique is not for eyelid skins and also not for home use regardless.