When I was only 19 years old, I already had dark spots on my face, tear troughs, splayed lines at the corners of my mouth, and short hair on my forehead. What to do -_-

The dark spots on your face should be freckles, unless you got sunburns from military training. Freckles have a genetic component. The splayed lines at the corners of the mouth are nasolabial folds. The above two are generally more likely to occur if the skin is dry. Tear troughs may be caused by eye bags or deep lines around the eyes. The fuzz on the forehead is generally seen when the whole body is very hairy, and it is mostly caused by hormones.