Everybody has one. A tricky/embarrassing/pressing question about their skin that they've just never had answered. Until now that is. We know we're lucky to have some of the best dermatologists in the business at the end of a phone line, but never let it be said that we don't share the wealth. 

In the US, having a 'derm' is like having a dentist, i.e. everybody has one. But in the UK, we're seriously lagging behind. Unless you're very well off, have been referred by your GP or spend your days attending in-depth, science-lesson-type presentations about new skincare research (that's us), you may never have had the chance to get the answers you really need.

That's why we put out the call for 50 of the most tricky and baffling questions about skin and put them to our best-loved derms, be they Hollywood's most sought after skincare doctors or internationally recognised pioneers in the field of skin research. No stone has been left unturned, no question too cringeworthy, so whether you want the low-down on adult acne or to find out what SPF you really ought to be wearing in the UK, we've gone and done the hard work for you.

Click through the gallery above to discover the answers to the trickiest skincare questions out there.