I have a small white corneal ulcer, no pain or discharge just minor dry eye. my doctor cannot see me for 3 days, any tips to get me through till then?

Antibotics: Just make sure you have antibiotics drops or ointment. Otherwise if the symptoms are minor i would not worry too much.

Yes: If it is only related to dry eye, frequent use of unpreserved artificial tears should allow the "ulcer" to heal. If the "ulcer" is not improved in 12 hours, go in as an emergency if they will not see you, find another eye doctor.