sorry to hear you're experiencing this. it must be uncomfortable! it's really impossible to say what could be causing this without a physical examination. your best bet is to make an appointment with your primary care provider and let him or her take a look at your toe. because the range of possible causes is so wide (and depends a lot on your physical history medications and so on) only your health care provider can provide a diagnosis. i hope you're able to get this resolved quickly!
what does it mean when your toe starts swelling and turning white underneath? with itching and pain?