Would using a lash serum containing prostaglandin analogues still darken my green eyes if I use it on my brows?

I have green eyes with flecks of amber. I know that these prostaglandin analogues can potentially darken eye color (excluding blue and brown eyes), but is that only if it gets directly into the eye? I used to use lash serums on my lashes, but after learning about the risks associated with them, I stopped. So my question is would it still darken my green eyes/cause the amber to expand more if I use it sparingly on my brows? Or will it absorb into the skin and still affect my eye color? Thank you!