The results were never the problem
Retinoids ask a lot of your skin before they give anything back. The first weeks bring redness and peeling, tight patches along the nose and jaw, a burn when moisturizer meets raw skin. Dermatology has a name for it, retinoid dermatitis, and a protocol for getting through it. Some skin settles. Some never stops reacting.
So people stop. A product that works ends up in a drawer with the cap on, and the person who bought it carries a quiet sense of having given up on something that was supposed to help.