TCA CROSS day by day: what to expect

On the treatment day, the pinpoint areas can sting or feel warm, with visible redness around each application site. Early swelling may make the marks look more noticeable than the original scars. Over the next few days, the treated spots commonly become darker or develop a firm surface crust. This is part of the controlled skin response to trichloroacetic acid, rather than a sign that the final result can already be judged.

As the crusts loosen, new skin appears underneath. Flaking should be allowed to come away naturally. Pink, brown or uneven colour can remain after the surface closes, especially in skin that marks easily. Scar texture changes gradually, so comparison with baseline photographs is more useful than checking the area repeatedly in a mirror.

Follow the treating clinician’s cleansing and ointment instructions, keep the area protected from rubbing, and do not pick, scratch or peel crusts. Avoid adding acids, retinoids, scrubs or fragranced products until the clinician says the skin barrier has recovered. Use the recommended sun protection because ultraviolet exposure can deepen temporary dark marks. Read more about the material used in [Trichloroacetic Acid](/materials/trichloroacetic-acid/) and the procedure in [TCA CROSS](/treatments/aesthetic-procedures/tca-cross/).

Contact the clinic promptly if pain is worsening rather than easing, redness is spreading beyond the treated points, swelling becomes marked, or the area develops pus, a bad smell or fever. Seek urgent medical care for facial swelling that affects breathing or vision. Do not remove a crust to inspect the skin if infection or an unexpected reaction is suspected.

Ask when you may restart your usual skincare, which cleanser and protective ointment to use, how to manage persistent darkening, and when the clinician wants to review the treated scars.