Retinol.

"Rock Retinol is one of my two favorite over-the-counter retinoid recommendations. It's very affordable, very gentle, and accessible. You can find it at your local Target or Walmart. Retinoids work by improving the uneven tone and texture from sun exposure. They're going to help reduce the look of post-inflammatory marks and hyperpigmentation. It's gentle enough for beginners. If you're a beginner with extremely sensitive skin, use only a pea-size amount to cover your entire face, avoiding your eyes and the corners of your nose, and make sure you moisturize on top. Start with three to four nights a week and increase if your skin can tolerate it."

"One of my favorites is the Rock Retinol. Rock is sort of one of the OG brands when it comes to developing a stable retinol that can be incorporated into a variety of products, but they make an excellent face cream that I think is great for beginners. The other thing that I really like about this is that it's formulated in a really rich moisturizing base so you're sort of achieving two skincare steps in one. It can act as your topical retinol and your moisturizer."