Waiting four weeks to get into someone is unacceptable. You should not sit still for this nonsense. You need to get that thing biopsied now. If they can't get you in, get your rear to a different doctor. You don't need a referral to see an oral surgeon or an ENT. Get on the phone tomorrow and make this happen. It may not be serious, but if it is 4 weeks is time for it to get out of hand. The first thing that you will learn from everyone here is you have to learn to be your own advocate. It is not the insurance company's or GP's life that is on the line.... it is yours. Start thinking like that and make demands to get seen. Are you willing to let a for profit HMO or insurance company impact you in a way that may let something dangerous grow into a later stage or even untreatable disease? They don't care, it's up to you. Three enlarged nodes and a sore the doctor doesn't recognize... those are some red flags.