You raise many questions which are hard to answer without specific details. First, many insurance plans have abandoned the idea of "pre-existing conditions", especially if your insurance comes from a large company like a hospital. It's a much bigger problem when insurance is purchased on the individual market, and when a company is small (where one person with high health costs can drive up everyone's premiums). There is no way to "withdraw" anything from your medical record, unless it's a true error (and even in that case, it's basically impossible also). Rotating with physicians who have treated you is a complicated situation. Most of the discomfort would be for your friend, so if he/she doesn't mind, then there isn't much of a problem. If you have a longstanding / continuity relationship with a physician, then they should not supervise / grade you due to the obvious conflict. Much of the decision here is whether your friend wants to keep their personal medical life and their work life seperate or not. There is more privacy if they do so, and more convenience if they do not.