Your skin stopped producing the molecule β-sitosterol, which keeps your barrier thick enough to conceal your blood vessels.
When estrogen drops (which happens to every woman eventually), it triggers a chain reaction.
Your skin cells slow down production of β-sitosterol, the structural molecule that keeps your barrier thick.
Some women's skin slows down gradually, and their barrier stays relatively thick.
But for others, and I see this in my practice constantly, their barrier thins more rapidly.
Think of it like this:
If you took two pieces of fabric, one thick like denim, one thin like tissue paper, and held them over a red surface, which one would show the red through?
The tissue paper, obviously.
That's exactly what's happening to your face.
Without enough of this structural molecule, your skin becomes paper-thin, like tissue paper instead of denim.