When your skin reacts, stop

Something you put on your face has made it red, or sore, or bumpy, or all three. The instinct at that moment is to buy something calming. It is the wrong instinct, and it is the one the whole industry is arranged to encourage.

Here is what we would do instead. With one thing said first, because it is the only part of this that is urgent.

The part that is not our department

We are a shop. We sell cosmetics, we do not diagnose anything, and nothing on this page is medical advice.

Stop reading and speak to a pharmacist or a doctor if any of this applies:

• Skin that is swelling, particularly around the eyes, lips or mouth.
• Blistering, weeping or broken skin.
• A rash spreading beyond where you applied anything.
• Pain rather than discomfort.
• Anything at all affecting your breathing. That is an emergency, not a shopping question.
• A reaction that has not begun to settle after a few days of leaving it alone.

And if you have a diagnosed skin condition or are using something a clinician prescribed, that relationship outranks anything we could write. Take it to them.

Everything below is for the ordinary case: an unhappy face, no emergency, and a shelf of products with no idea which one did it.

Stop. Do not swap.

The single most common mistake is treating a reaction as a gap in the routine — something is wrong, therefore something is missing, therefore buy the calming thing. What that actually does is add a new variable to a routine that already has too many, at the exact moment your skin is least able to tell you anything useful.

Go down to two products. A plain cleanser, at night only, and a plain moisturiser. Nothing that tingles, nothing acidic, no retinoid, no exfoliant, no vitamin C, no clay, no scrub, and nothing bought this week to fix this week’s problem. Ideally fragrance-free, because fragrance is the most common single culprit in cosmetic reactions and you are trying to reduce suspects rather than acquire them.

If your skin will tolerate sunscreen, keep it — irritated skin is not improved by a sunburn. If it genuinely will not tolerate anything at the moment, a hat and the shady side of the street will do for a week.

Then wait. Most reactions to a cosmetic settle in days rather than hours once the thing causing them is gone, and the waiting is the part nobody does.

What the pattern tells you, and what it does not

While you are waiting, it is worth noticing which of these you have. It will not give you an answer, but it narrows the field.

• Immediate sting that fades in minutes, no redness afterwards. Common with acids and with high-percentage actives on skin that is already dry. Often about the state your skin was in rather than the product itself.
• Redness and heat that arrive within a day and cover roughly where you applied it. The most straightforward pattern: something in that product does not agree with you at that strength or that often.
• Itch, small bumps, or a rash that appears after days or weeks of happily using something. The pattern most worth taking to a professional, because it is the one that does not resolve by reasoning about it. Delayed reactions are also the reason "I have used this for months" is not proof of anything.
• Spots, in places you normally get spots, a week or two after a new step. The murkiest category, and the one dealt with below.

"It is just purging" is doing a lot of work it has not earned

The idea is that some products speed up how quickly skin turns over, which brings existing congestion to the surface sooner than it would have arrived on its own. That is a reasonable mechanism for a small group of ingredients — retinoids and the acids — and it is not a reasonable explanation for a moisturiser, a toner, an oil or a sheet mask, none of which do anything of the kind.

Two questions cut through most of it.

Is it a product that could plausibly do that? If it is not a retinoid or an exfoliating acid, the answer is almost certainly no, and the word is being used to keep you buying through a reaction.

Is it happening where you normally break out? Congestion surfacing early should appear where congestion already was. New spots in a place you have never had them is a different event wearing the same word.

We should be honest about the limits here: the published evidence for purging as a distinct, well-characterised phenomenon is thinner than the confidence with which the term is used online, including by people selling things. Six weeks is the usual figure quoted for how long to tolerate it. If you are past that and still worse than you started, it is not a phase.

Patch testing, done properly

Almost everyone has heard of it. Almost nobody does the version that works.

Put a small amount on the same spot — the inner forearm, or just in front of the ear along the jaw if you want somewhere more like face skin — twice a day for five to seven days. Not once. A single application on the back of your hand tests for nothing except the fastest possible reaction, and the reactions that catch people out are the slow ones.

It is tedious, and it is the only tool available that costs nothing. It is most worth doing for anything you will leave on, anything with a botanical extract high on the list, and anything you have reacted to a relative of before.

Coming back

Once your skin has been calm for a week or so, add one product back. One. Give it two weeks before the next one. Yes, that means the full routine takes a couple of months to reassemble, and yes, most people find they stop before they get to the end — not out of discipline, but because they stop missing the parts they removed. We have written about why that keeps happening.

What you get for the two months is the thing the shelf of half-used bottles never gave you: you will know which product it was. That knowledge is worth more than any of the products, because it is the only thing that stops the same forty euros being spent again next year.

When you are ready to rebuild, read your skin first and then build the routine — in that order, and with three steps rather than eight.