There are many pimples on my body.how to get rid of them?

Need scientific Rx: I'll assume this is common acne on your trunk. This almost always requires a systemic antibiotic -- your physician can choose what's right for you, and what topical treatmetn to use as well. If this does not work, a dermatologist has the big guns that are certain to clear you, though the rx is a bit dangerous and unpleasant. Good luck. You can get effective treatment.

Acne: There are over the counter medication such as benzoyl peroxide. If it fails then see a doctor.