i can understand your concerns,if by pimples you mean Acne
then apart from topical therapy you need some oral anti biotics regularly,which can be continued according to the response.There are different kind of anti biotics available and your doctor would start you on according to the severity and the grade of the acne.Once the acne has been controlled then there several effective options available for dull and tanning
skin depending upon the skin type you have.
For example AHA chemical peels
and laser skin resurfacing
,all of these remove the superficial skin surface and a new fresher and lively skin glow can be obtained.
In the meantime kindly avoid sunlight as much as possible,wear a sunblock of more than 30 SPF throughout the day ,eat a healthy balanced diet,have some good Vitamins,drink plenty of water and have good night sleep.
i hope you ll get good results.