Is it Regimen or Regime?

When you're talking about your skincare process, is it regime or regimen? I always thought it was regimen because of Rashida Jones and Emma Roberts in this clip:

(Who else loves a good rom com? Tell me your fave in the comments!)

But as I was reading a product description on a skincare brand's website, I saw "regime" which got me thinking, is there a secondary definition of regime? Here's the answer according to the Merriam Webster...

Definition of regime:

Definition of regimen:

So both are correct.