Some redness is to be expected when the skin is injured. However redness along with one or more of the following, fever, swelling or tenderness near the wound or insertion site, should be reported to the doctor.
Observing the site for swelling is a good way to determine if there is more drainage. If during the two week period the drainage gradually subsided, that is an indicator that the wound was healing. Because of the wound healing process, your doctor is probably comfortable not reinserting the drain.
Yes you can, if you touch around the wound or the drainage and then touch another part of the body or touch yourself. If you touch the drainage port to the measuring cup or contaminated dressings, you increase the risk for infection spreading into the wound and drain container. You reduce the risk for infection with good hand washing before and after care and after touching dirty dressings.