The chain, formerly known as Lasercare until a rebrand at the start of the year, is refurbishing its 17 sites and plans to open a further 33 in the next two years.
Unity's brief is to raise the brand's profile and promote the stores, said marketing manager Anthony Brown.
Sk:n was taken over in January by Graphite, the venture capitalist behind the Wagamama noodle chain.
It continues to use Hards PR for trade work.
