More and more people are having ‘tweakments’. But what do we really know about the long-term effects?

Mona Lisa smile … Leonardo’s masterpiece after a couple of tweakments. Illustration: Lisa Sheehan/The Guardian

From trout pouts to frozen foreheads, we’ve all seen people who look a bit odd after overdoing the Botox or facial fillers. Then there are the horror stories of people left blinded or with festering wounds after botched cosmetic injections.

The market for non-surgical cosmetic treatments is booming; the desire for plump, youthful-looking skin or the perfect “Instagram face” apparently trumping any fears of bad results or medical complications. Injections of botulinum toxin and dermal fillers are now the most common non-surgical cosmetic procedures worldwide, and the market for such “tweakments” is anticipated to grow a further 15.4% by 2030.