All you need to do is control ur diet. Put a limit on taking oily food,pickles. Try to take fruits with more anti oxidant, Grape , red wine etc may help, Apart from that take as much as water possible. More intake of water will result in more urination,which in turn wash away the impurities from ur blood.
for external skin, apply a home made facial, mix lemon with multani mitti and turmeric(haldi) and apply every day on ur face, this will reduce the black scars, external growth of pimples.