Safe to Use TCA Peel on Just a Part of the Face?

TCA peels can be done on small areas of the face or individual spots but should only be done by a doctor with years of experience since you don't want to scar up your face with a home treatment. A cortisone cream should be applied 3-4 times the first day and twice a day thereafter for 10 days to prevent scarring and irritation. A sunscreen is also necessary. Home TCA peels should not be above a 10%TCA and can be done every 2-4 weeks.

I agree, the strength of TCA that you are contemplating can in fact cause scarring.  The more passes, the deeper the peel even with a lower strength solution.  Higher percentage peels (greater than 10 percent) should be done by a physician or at least under direct physician supervision.  Having said that, it is possible to just peel isolated aesthetic subunits of the face as long as the entire subunit is treated.  If that rule is followed, the peeled area should transition nicely into other nontreated areas.