If you are given antibiotics to treat a STD, it is important that you take all of the drug prescribed to you, even if the symptoms go away. Also, do not take someone else's medication to treat your infection; it may make it more difficult to treat. Here are some specific STD treatments:
LDL's are cleared by the liver. HDL is generally fatty acid poor and cholesterol ester rich. It contains a different apolipoprotein which helps the body tell it apart from LDL. Simply put, it transports cholesterol back to the liver from other areas of the body.
The difference between HDL and LDL (and VLDL for that matter) is the size/density. Lipoproteins are made up of a few different substances, but the difference between the composition of the VLDL and HDL is the amount of lipids (fat) inside the lipoprotein. The density of the proteins is almost entirely dependent on the amount of fat in the diet, which is why saturated fats are protective.