A woman tested a lipstick in Sephora. And every woman's nightmare has become her reality.

In what is arguably a makeup lover‘s worst nightmare (just in time for Halloween!), a woman is reportedly suing Sephora after claiming she contracted herpes from one of their lipsticks.

According to TMZ, a Californian woman has filed a suit claiming she visited a Sephora store in Hollywood in October 2015 where she sampled a lipstick from one of the “common use” tubes on display. She claims it gave her herpes on her lips, and says she never had herpes or cold sores before the makeup shopping trip.

She’s reportedly suing the makeup retailer for ’emotional distress’ over an “incurable lifelong affliction” that she claims she now has and says Sephora failed to adequately warn her and other customers of the risk of getting herpes from lipstick samples.

A spokesperson for Sephora told Fashionista.com , "While it is our policy not to comment on litigation, the health and safety of our clients is our foremost priority. We take product hygiene very seriously and we are dedicated to following best practises in our stores."

It's happened before. A US woman tried to sue M.A.C in 2013 after claiming she contracted a cold sore from a Rhianna x M.A.C lipstick applied to her by a M.A.C representative at the singer's concert.

Considering how many people could be touching testers and applying them to their face, it's a given that while testers may be useful to see the consistency or colour of a product, they're not always the most sanitary.

A study on makeup tester germs run by Rowan University in 2011 found that "More than half of all testers were contaminated, and we found staph, strep, and E. coli bacteria from feces....you can contract pink eye, infections, or even viruses like herpes or hepatitis."

And it's true that sharing cosmetics can lead to sharing cold sores.

In a blog post for Huffington Post published in 2011, NYC cosmetic dentist Thomas P. Connelly, D.D.S. wrote that herpes type 1 (oral herpes) can easily be spread by sharing any products that go near your mouth, including lipstick, lip balms, cutlery, cigarettes, toothbrushes or even razors.

Oral herpes is also much more prevalent than you might expect - it's estimated that 70 per cent of the population carries the virus. It doesn't have to be 'active' i.e noticeable to be spread either.

Fortunately, there are plenty of ways you can test makeup safely. Avoiding applying products to your eyes and lips is recommended as well as asking a salesperson to prep the tester, which involves them disinfecting with alcohol and applying with a disposable or fresh makeup tool.