Let’s assume I have to leave the house in 10 minutes – and I just notice my sunscreen is expired. Do I use the expired cream or go 'screen-free?

Definitely use the expired sunscreen. Many sunscreens are made with physical blockers like zinc oxide and titanium dioxide, which are more stable than chemical sunscreens such as oxybenzone and can last beyond their printed expiration date. And if you haven’t opened the bottle yet or you've stored it in a cool, dry spot (as in: not your bathroom!), then it’s even more likely still at full power. If it's within six months of the expiration date, slather it on. It’s a lot more dangerous to face ultraviolet radiation without protection.

I usually don’t use a face cream because I’m too lazy to lather up different products. Do I skip moisturiser altogether or use the body lotion on my face?

Use the body lotion – but read the label first. As long as the first ingredient is water – not oil – it won’t be that bad for your skin. Even better if you see any of these good-skin terms, too: “water-based”, “oil-free,” or “non-comedogenic”. And if you don’t, as long as you don’t make a habit of it, your skin should be in the clear. For the one-time hit that evening, you'll probably get away with it without any issues, and you'd be worse off allowing your skin to dry out all night and become inflamed.

My pricy new skin treatment burns and makes my skin a little red for a few hours. Do I keep using it and push through the pain – or stop using it ASAP?

Call it quits. Your skin should never get worse before it gets better – period. Any treatment that causes redness or burning isn't helping; in fact, your symptoms are key signs of inflammation, which can weaken your skin’s outer barrier and, ironically, make existing complexion concerns worse. (Yeah, definitely not what you're going for.) Cut your losses and give the product to a friend and use a gentle cleanser and moisturiser until your skin goes back to normal.

What if I have a horrible pimple last minute before an important event, and don’t have any of my go-to products. Can I use toothpaste or antibiotic cream?

Antibiotic cream, yes – toothpaste, no. A topical antibiotic intended for cuts and scrapes is a perfectly acceptable option to use for a pimple. Toothpaste? Not so much. It may be too harsh for delicate skin. So, dab on a little first aid cream and call it a night.