So if I had a rash that started on my arm then I let it go for 12 years without seeing a doctor I could say "hey I haven't been to the doctor in 12 years" but I'm guessing at some point I'd be a huge mess and either die or scratch all the flesh off of my body. But if I'd gone to the doctor and had it cleared up when it started...

It depends how much you trust your doctor. If your doctor has in the past treated these problems by slashing the arm off live on CNN in the cheery supposition that some sort of well-functioning arm will grow back without any form of outside help, and if he further appears to believe that even if it doesn't, hey, it's not his arm anyway, then frankly I'd keep the rash...

Peter