According to limited sources* bee venom therapy (BVT) is an effective scar treatment. * (Singh, Ratner et al and Lee)

Having scars stung by bees resulted in improvement of scar appearance by reducing, soften, and flatten scar tissue, and toning down the color of the scar.

Of the 18 substances present in bee venom the enzyme hyaluronidase is mainly held accountable for these results. Also internal scar tissue is thought to benefit from this alternative therapy.

“Charles Mraz, a beekeeper in Middlebury, Vermont who has popularized bee venom therapy for the past 60 years, says that it is reasonable to try bee venom therapy in any clinical situation where nothing else works.” [...] “Keloids and other scar tissue are broken down and softened by the substances in the venom, and can flatten out and fade in color.” source: CareCure Forums

This alternative scar treatment isn’t suitable for people who are allergic to bee stings so the first step should be an allergy test.

More info and before and after photo’s of someone who has actually applied bee stings to a scar here: before and after.