Knowing the limits

When to stop reading and see a doctor

I write about ingredients. That is genuinely useful, and it is also a small thing next to what a clinician can do in ten minutes with your actual skin in front of them. So this is the honest edge of this whole site: the moments where the right move is to close the tab and book an appointment.

Nothing here is a diagnosis, and I am not a dermatologist. It is a list of the signs that are worth taking to someone who can examine you, in plain words, so you can recognise them early rather than talking yourself out of them for another six months.

The signs worth booking for

A mole or spot that is changing

The one thing on this page worth acting on quickly, because time genuinely matters.

It is asymmetrical: one half does not match the other.
The border is ragged, blurred or uneven.
The colour varies across it, or it has turned very dark.
It is wider than about 6mm, roughly a pencil eraser.
It is changing: growing, thickening, or looking different from your others.
It bleeds, itches, crusts, or has not healed in a few weeks.

A new or changing spot is worth a look even if it seems small. Nobody will think you wasted their time.

Acne that hurts or leaves marks

Over-the-counter care has a ceiling, and pushing past it with more products usually costs skin.

Deep, painful lumps under the skin that last for weeks.
Breakouts that leave scars or dents rather than fading.
Months of consistent, sensible care with no real change.
Acne that is affecting your sleep, your mood, or how you live.

Prescription treatment exists precisely for this, and starting it earlier means less scarring to treat later.

Signs of infection

This is the group where waiting is the wrong call.

Skin that is hot, swollen and painful.
Redness that is spreading, especially if it spreads quickly.
A fever alongside a skin problem.
Pus, or a wound that is getting worse rather than better.

Treat this as urgent rather than something to watch for a few days.

A reaction bigger than irritation

Stinging that settles is irritation. These are not that.

Swelling of the lips, tongue, eyes or throat, or any trouble breathing. Get emergency help immediately.
Blistering, peeling, or skin that is breaking open.
A rash spreading well beyond where you applied anything.
A rash that started after a new medicine.

Stop using everything new, and get seen. Working out which ingredient did it can wait.

Anything persistent, spreading or worsening

The plainest rule on this page, and the one that catches what the other groups miss.

A patch, rash or lump that has stuck around for months.
Something that keeps coming back in the same place.
Sudden or patchy hair loss.
Any skin problem that is getting steadily worse despite reasonable care.

If you have been quietly worrying about something for a while, that is reason enough.

What to bring to the appointment

You will get more out of a short appointment if you arrive with these. None of it is homework, it is just the information that is genuinely hard to reconstruct on the spot.

Photos taken over time, with dates. A clinician sees your skin on one day; your photos show the pattern.
A list of everything you put on your skin, including cleansers, sunscreen and anything you use occasionally.
When it started, and what changed around then: a new product, a new medicine, stress, a move, a season.
What you have already tried, how you used it, and for how long. Most treatments need weeks before a verdict.
Any medicines and supplements you take, and relevant family history.
Your questions, written down. Appointments are short and it is easy to forget the one you came for.

If you keep a shelf here, your shelf list is already most of that second point. Copy it and take it with you.

This site's lane, and a doctor's

What this site can honestly do

Explain what an ingredient is and what it actually does.
Tell you how strong the evidence behind it is.
Flag when two things you own work against each other.
Translate a label into plain English.
Show its working, every time. How we score sets out the method.

What needs a clinician

Looking at your skin, and at the thing you are worried about.
Naming what it is. No website can diagnose you.
Prescribing, and monitoring how you get on with it.
Knowing your history, your medicines and your risks.
Anything on the list above.

These are not competing. Understanding your ingredients makes you a better patient: you arrive able to say what you have used and for how long, which is exactly what a clinician needs and rarely gets.

Sources

Health services differ by country. If you are not in the UK, the signs above still stand; the number you call does not. When something looks like an emergency, treat it as one.