Sun tan is quite common because of unprotected sun exposure. This is because of excess production of melanin or excess accumulation of melanin in the skin layers  in response to UV rays. Moles are formed due to arrest of melanin producing cells in skin layers where they continue to produce melanin which collects to form flat or raised moles. Tan can be treated by using certain depigmenting creams which contain glycolic acid, kojicacid, alpha arbutin etc which have to be used under the supervision of a  qualified dermatologist. Procedural treatment like chemical peels and laser toning with QS yag laser can help. Most important is religious use of sunscreens to prevent further tan and improvement of skin. Moles can be treated by radiofrequency ablation, punch excision or Q-switched yag laser. So please consult a qualified Dermatologist.