It is probably hormones and nothing to worry about and at your age camouflage is the only recommendation I can think of at this time. I remember going thru the same thing and as I got older it took care of itself. Concealers work well to cover these up.
Just make sure you wear a good moisturizer during the day with SPF. You're never too young to prevent skin damage. Dark spots are signs of pigmitation which you can get from sun. Cover your face if you tan in the tanning bed. In the meantime, concealer will cover.
It is only for changing of age. Everyone faces this problem in this age. So don’t worry be happy.