It is very similar to the closely related Common Mouse Ear, Cerastium fontanum so here are a few differences to look out for.
Sticky Mouse Ear is also known as Clustered Mouse Ear, The flowers are clustered together in a tight flower head. Common Mouse Ear flowers are more spread out.
The green sepals of Sticky Mouse Ear are sometimes tipped with red. The entire plant is covered with fine hairs and at the tip of each hair is a small gland that secretes a sticky substance that gives the whole plant a slightly sticky feel.
Characteristically the hairs on the sepals extend beyond the tips of the sepals, with Common Mouse Ear they don’t.
Sticky Mouse Ear is a member of the Pink or Carnation family, a family that also includes the Campions. I can see several similarities between this and the hairy Red Campion. It is native to the UK and Europe but it is present on most continents as an introduced species.
Species: Cerastium glomeratum