Claire DanesActress Claire Danes is a celebrity spokesperson for 'Latisse', an eyelash growth treatment from the makers of Botox, and also a regular user, but she may have suffered one of the product's side effects.

An anonymous source has been quoted in New York Post's 'Page Six' that Danes' makeup artist has to plaster on concealer to cover the bruise-like purplish and yellowish skin discoloration that the actress' use of lash-growth drug has left around her eyes.

Cited as a possible side effect, skin darkening joins redness, itchiness and alternate hair growth as unwanted consequences that may occur with use of the serum.

While the 31-year-old Emmy-winning star admits on her Latisse blog to experiencing redness during the first week she was on the lash-growth serum, product maker Allergan is calling foul on the talk of skin darkening.