I look older than I really am. I'm wondering what is causing the problem, and how it can be remedied. (Photo)

There are many different things that can contribute to
looking older than your years, including lifestyle habits (smoking, not getting
enough sleep) and environmental factors (sun exposure). To preserve a youthful
look for as long as possible, it’s important to protect the health of your skin
with a high-quality skincare regimen that includes a daily SPF sunscreen. You
may also consider looking into nonsurgical med spa treatments like chemical
peels or laser skin resurfacing to help keep signs of aging at bay for longer
and reverse existing damage, while dermal fillers or BOTOX® can reduce the
appearance of wrinkles that have already developed.

Be sure you are using a medical grade sunscreen.  I would suggest a skin care routine at home that includes a medical grade Vitamin C product and Retin A.  Start with a low dose and work up to a higher dosage.  Try using it every night.  You may be a candidate for a medium to deep grade chemical peel.  I hope this helps.